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

<!-- ⚠️⚠️ Do Not Delete This! bug_report_template ⚠️⚠️ --> <!-- Please read our Rules of Conduct: https://opensource.microsoft.com/codeofconduct/ --> <!-- 🕮 Read our guide about submitting issues: https://github.com/microsoft/vscode/wiki/Submitting-Bugs-and-Suggestions --> <!-- 🔎 Search existing issues to avoid creating duplicates. --> <!-- 🧪 Test using the latest Insiders build to see if your issue has already been fixed: https://code.visualstudio.com/insiders/ --> <!-- 💡 Instead of creating your report here, use 'Report Issue' from the 'Help' menu in VS Code to pre-fill useful information. --> <!-- 🔧 Launch with `code --disable-extensions` to check. --> Does this issue occur when all extensions are disabled?: No <!-- 🪓 If you answered No above, use 'Help: Start Extension Bisect' from Command Palette to try to identify the cause. --> <!-- 📣 Issues caused by an extension need to be reported directly to the extension publisher. The 'Help > Report Issue' dialog can assist with this. --> - 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](https://marketplace.visualstudio.com/items?itemName=ms-vscode.azure-account) 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 t…