message: ci: Update bundle-size-artifacts pipeline for pnpm
  This pipeline is unique in that it runs from the root (client) directory
  and installs the client dependencies. This PR corrects it to use pnpm
  now that the client is using pnpm.
diff: @@ -22,6 +22,8 @@ trigger:
  - package-lock.json
  - lerna.json
  - lerna-package-lock.json
  + - pnpm-lock.yaml
  + - pnpm-workspace.yaml
  - tools/pipelines/build-bundle-size-artifacts.yml
  - tools/pipelines/build-client.yml
  - tools/pipelines/templates/build-npm-package.yml
  @@ -41,6 +43,8 @@ extends:
  taskBundleAnalysis: true
  taskPublishBundleSizeArtifacts: true
  taskBuildDocs: false
  + packageManagerInstallCommand: 'pnpm i --frozen-lockfile'
  + packageManager: pnpm
  buildDirectory: .
  tagName: bundle-artifacts
  poolBuild: Large
  