Issue title: Button not showing on tasks in Salesforce integration
 Issue body: #### Relevant integration (if any): Salesforce

### 🐛 Describe the bug

toggl button salesforce integration issue - user can see button on some pages (e.g. profile page, attached), but not on the task lists
![image](https://user-images.githubusercontent.com/18132080/59045664-ca231900-8880-11e9-9d84-fd779b13ca22.png)
But it's not showing on the task lists
![image](https://user-images.githubusercontent.com/18132080/59045698-d909cb80-8880-11e9-9259-c79e30917046.png)
Screenshot from the wiki showing where it should appear:
![image](https://user-images.githubusercontent.com/18132080/59045724-e6bf5100-8880-11e9-80a7-a03af71329d5.png)



### Other details or context
conversations/22174259794

 Comments: 
 Comment 0: [case reference](https://app.intercom.com/a/apps/ayixs927/inbox/inbox/2759100/conversations/26301393618)
{'source': 'GithubIssues', 'repo_name_with_owner': 'toggl/track-extension', 'issue_id': 453099114, 'repo_stars': 1023.0}