[Codespaces] machine-overridable, experimental setting changes its value when the focus changes

Does this issue occur when all extensions are disabled?: No

• Version: 1.66.0-insider
• Commit: 3e5c7e2c570a729e664253baceaf443b69e82da6
• Date: 2022-03-14T05:14:23.074Z (16 hrs ago)
• Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.87 Safari/537.36

Steps to Reproduce: This reproduces with the "Azure: Authentication Library" setting from the Azure Account Extension. Definition in package.json: https://github.com/microsoft/vscode-azure-account/blob/1268dab932c324a63f9875b96e3cf6dca742cfa2/package.json#L224

1. In Codespaces, install the Azure Account Extension
2. Open user settings with the "Preferences: Open Settings (UI)" command
3. Select user settings and use the drop down on the left to navigate to "Extensions" -> "Azure configuration".
4. Modify the "Azure: Authentication Library" setting and then click away from the dropdown box to change focus as shown below. The setting reverts back to the default value.

https://user-images.githubusercontent.com/22795803/158266976-6c613eff-4c9e-4dff-84ab-38ad330e6692.mov

More info: This setting does not appear when searching the user settings even though it can be navigated to in the user settings tree. It does appear in a search of the workspace settings as expected.

Related: https://github.com/microsoft/vscode-azure-account/issues/482