Issue title: Lens 5 does not start if shell autostarts tmux
 Issue body: **Describe the bug**
Lens 5 does not start

**To Reproduce**
Steps to reproduce the behavior:
1. Use ZSH with oh my zsh tmux plugin and `ZSH_TMUX_AUTOSTART=true`
2. Launch Lens
3. Lens is stuck on loading window

**Expected behavior**
Lens will launch

**Screenshots**
![image](https://user-images.githubusercontent.com/6400093/124693498-e6dc2000-df22-11eb-9776-c78ccf3ea7bf.png)

**Environment (please complete the following information):**
- Lens Version: 5.0.2
- OS: macOS
- Installation method: DMG

**Logs:**
When you run the application executable from command line you will see some logging output. Please paste them here:
```
info: 📟 Setting Lens as protocol client for lens://
info: 📟 Protocol client register succeeded ✅
info: 🚀 Starting Lens from "/Users/omja/Library/Application Support/Lens"
info: 🐚 Syncing shell environment
error: shellEnv: TypeError: Cannot read property 'split' of undefined
info: 💾 Loading stores
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-user-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-cluster-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-hotbar-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-extensions.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-filesystem-provisioner-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-weblink-store.json
info: 🔌 Starting LensProxy
info: [LENS-PROXY]: Proxy server has jonathan54@example.com:62668
info: 🔎 Testing LensProxy connection ...
info: ⚡ LensProxy connection OK
info: 🖥️  Starting WindowManager
info: 🧩 Initializing extensions
info: [EXTENSION-DISCOVERY] loading extensions from /Users/omja/Library/Application Support/Lens
info: [EXTENSION-INSTALLER] installing dependencies at /Users/omja/Library/Application Support/Lens
info: [WINDOW-MANAGER]: Loading Main window from url: http://localhost:62668 ...
info: [EXTENSION-INSTALLER] dependencies installed at /Users/omja/Library/Application Support/Lens
info: [EXTENSION-DISCOVERY] watching extension add/remove in /Users/omja/.k8slens/extensions
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/extension-store/lenscloud-lens-extension/auth-token-store.json
error: [EXTENSIONS-LOADER]: can't load main for "lens-telemetry": TypeError: Cannot create a second singleton while creating a first {"extension":{"id":"/Users/omja/Library/Application Support/Lens/node_modules/lens-telemetry/package.json","absolutePath":"/Applications/Lens.app/Contents/Resources/extensions/telemetry/lens-telemetry-5.0.2-latest.20210705.2.tgz","manifestPath":"/Users/omja/Library/Application Support/Lens/node_modules/lens-telemetry/package.json","manifest":{"name":"lens-telemetry","version":"5.0.2-latest.20210705.2","description":"Lens IDE telemetry","main":"dist/main.js","renderer":"dist/renderer.js","lens":{"metadata":{},"styles":[]},"scripts":{"build":"webpack -p && npm pack","dev":"webpack --watch","test":"jest --passWithNoTests --env=jsdom src $@"},"files":["dist/**/*"],"devDependencies":{"@k8slens/extensions":"file:../../src/extensions/npm/extensions","@types/analytics-node":"^3.1.3","@types/node":"^14.14.14","@types/react":"^17.0.0","@types/universal-analytics":"^0.4.4","analytics-node":"^3.4.0-beta.3","conf":"^7.1.2","jest":"^26.6.3","mobx":"^6.3.2","mobx-react":"^7.1.0","node-machine-id":"^1.1.12","react":"^16.13.1","ts-loader":"^8.0.4","typescript":"^4.0.3","universal-analytics":"^0.4.23","webpack":"^4.44.2","webpack-cli":"^3.3.11"}},"isBundled":true,"isEnabled":true,"isCompatible":true}}
error: [EXTENSION]: failed to activate jonathan54@example.com: Error: [MobX] No annotations were passed to makeObservable, but no decorated members have been found either
info: [EXTENSION]: enabled jonathan54@example.com
error: [EXTENSION]: failed to activate jonathan54@example.com: Error: Error while obtaining machine id: Error: Command failed: ioreg -rd1 -c IOPlatformExpertDevice
/bin/sh: ioreg: command not found

    at ChildProcess.exithandler (child_process.js:304:12)
    at ChildProcess.emit (events.js:223:5)
    at maybeClose (internal/child_process.js:1021:16)
    at Socket.<anonymous> (internal/child_process.js:430:11)
    at Socket.emit (events.js:223:5)
    at Pipe.<anonymous> (net.js:664:12)
info: [WINDOW-MANAGER]: Main window loaded
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-user-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-cluster-store.json
info: [CLUSTER-STORE] requesting initial state sync
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-hotbar-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-extensions.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-filesystem-provisioner-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/lens-weblink-store.json
info: [CLUSTER-STORE] start to listen (1)
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/extension-store/lenscloud-lens-extension/auth-token-store.json
info: [STORE]: LOADED from /Users/omja/Library/Application Support/Lens/extension-store/lens-survey/preferences-store.json
info: [EXTENSION]: enabled jonathan54@example.com
info: [EXTENSION]: enabled jonathan54@example.com
info: [EXTENSION]: enabled jonathan54@example.com
info: [EXTENSION]: enabled jonathan54@example.com
error: [EXTENSION]: failed to activate jonathan54@example.com: TypeError: Cannot create a second singleton while creating a first
error: [EXTENSION]: failed to activate jonathan54@example.com: Error: Error while obtaining machine id: Error: Command failed: ioreg -rd1 -c IOPlatformExpertDevice
/bin/sh: ioreg: command not found

    at ChildProcess.exithandler (child_process.js:304:12)
    at ChildProcess.emit (events.js:223:5)
    at maybeClose (internal/child_process.js:1021:16)
    at Socket.<anonymous> (internal/child_process.js:430:11)
    at Socket.emit (events.js:223:5)
    at Pipe.<anonymous> (net.js:664:12)
info: [StorageHelper]: loading finished for /Users/omja/Library/Application Support/Lens/lens-local-storage/app.json
error: Can't find working API for the Kubernetes resource ingresses
info: [StorageHelper]: saving /Users/omja/Library/Application Support/Lens/lens-local-storage/app.json
info: [CLUSTER]: disconnect {"id":"8fd2dbea6c376e032d664b49b09852a1","name":"arn:aws:eks:us-east-1:453793470413:cluster/staging-use1","ready":false,"online":false,"accessible":false,"disconnected":true}
info: [CLUSTER]: unbind events {"id":"8fd2dbea6c376e032d664b49b09852a1","name":"arn:aws:eks:us-east-1:453793470413:cluster/staging-use1","ready":false,"online":false,"accessible":false,"disconnected":true}
info: [CLUSTER]: disconnect {"id":"c38b5de1f68b8e581300b360b41c0437","name":"arn:aws:eks:ap-southeast-2:453793470413:cluster/staging-apse2","ready":false,"online":false,"accessible":false,"disconnected":true}
info: [CLUSTER]: unbind events {"id":"c38b5de1f68b8e581300b360b41c0437","name":"arn:aws:eks:ap-southeast-2:453793470413:cluster/staging-apse2","ready":false,"online":false,"accessible":false,"disconnected":true}
info: SERVICE:QUIT
```

**Kubeconfig:**
Quite often the problems are caused by malformed kubeconfig which the application tries to load. Please share your kubeconfig, remember to remove any secret and sensitive information.
```
your kubeconfig here
```

**Additional context**
When `ZSH_TMUX_AUTOSTART=false` Lens opens properly.
 Comments: 
 Comment 0: Thank you for reporting this. There seems to be two issues. An error related to shell sync and one related to `ioreg` not being found.

Have you changed your `$PATH` to not have `/usr/sbin` in it?
 Comment 1: I have ran `ZSH_TMUX_AUTOSTART=true make dev` (and it launched fine) but will try it when running a released version.
 Comment 2: Just checked my path and can confirm that `/usr/sbin` is present
 Comment 3: I just found this https://github.com/sindresorhus/shell-env/issues/4, not sure what can be done here (apart from perhaps finding a different solution to gather environment variables)
 Comment 4: Thanks for finding that. And I realize that I am not running the tmux plugin so that is probably why I didn't run into the issue.
 Comment 5: If you run `ioreg` yourself, do you get output (don't post it if you do).
 Comment 6: I do get output when I run `ioreg`
{'source': 'GithubIssues', 'repo_name_with_owner': 'lensapp/lens', 'issue_id': 938431882, 'repo_stars': 19866.0}