Replace getDefaultShell and mergeDefaultShellPathAndArgs with getDefaultShellAndArgs

Also differentiate default from system shell

- get product configuration from server

Add vscode.env.webviewResourceRoot API

Part of #75795

electron-browser/ will already prevent this

Cannot reproduce the failure locally, additionally it was a timeout but
it's not an async test...

Fixes #75772

Part of microsoft/vscode-remote-release#730

Provide full TS symbol range when previewing definitions in VSCode

This reverts commit 28ab9ad9, reversing
changes made to 912ad66a.

This reverts commit 930290cf.

this change makes style changes visible to the mutation observer

fix: #75693