Support shadow root

[CGNonofr]

Experimental support for shadow root, for a better css isolation between the user app and the VSCode workbench.

A few parts of VSCode (regarding focus detection mainly) needed to be patched in order to work.
It also required some change so that styles are loaded in the ShadowDom

[github-actions]

🎉 This PR is included in version 16.1.0-shadow-root.1 🎉

The release is available on GitHub release

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[kaisalmen]

@CGNonofr is this ready for review or are you still implementing changes?

[CGNonofr]

@CGNonofr is this ready for review or are you still implementing changes?

I think so! I didn't really have the time to deeply test it but any fix can be done later as soon as nothing is broken without shadow dom

[kaisalmen]

LGTM, I will test it with monaco-languageclient once it is available and provide feedback.

[CGNonofr]

@kaisalmen @samuel-olivier 2 new commits:

• fix: fix product config override:
  A bug made it so if the user is providing a productConfiguration, it was overriding ALL properties of the default product configuration, including the quality which is reset from 'stable' to 'undefined'
  A "new" feature (experimentalEditContextEnabled) is enabled by default based on it, and is still a bit bugged (unable to paste in a search field for instance)
• fix: patch xterm to support shadow dom
  xterm webgl renderer is refusing to attach inside a shadow dom because of a wrong check. Until it's fixed and deployed in Xterm, I've added a notice and patched it in the demo (see Support shadow dom in webgl renderer xtermjs/xterm.js#5334)

[kaisalmen]

Thanks for the fixes, please go ahead.

[github-actions]

🎉 This PR is included in version 16.1.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀