prefer listed plugins to dependencies

[akosyakov]

What it does

It's a bug fix for #5379. We should either test and merge this PR for 0.10.0, or revert #5379. Right now it breaks all products which consumes from local files.

• fix plugin system should prefer listed plugins instead of dependencies #6036: otherwise the wrong version gets installed from a marketplace instead of from local vsix file for example

How to test

• put a flutter and dart VS Code extensions as vsix files to plugins folder
• start Theia
• make sure that dart extension is loaded from vsix file, not downloaded from the marketplace
  • you can do it by looking at backend logs
  • in order to be sure you can also build dart extension from sources that unzipping it not involved:
    • check out https://github.com/Dart-Code/Dart-Code under plugins instead of vsix
    • npm install
    • enable skipLibCheck in tsconfig and do npm run watch to compile

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[akosyakov]

@JPinkney It does not matter in which order plugins are deployed. They are only loaded when a frontend is connected by then all plugins should be already on the disk.

[akosyakov]

@vince-fugnitto @marcdumais-work it is important for 0.10.0

[JPinkney]

I've tested it both the way you listed and by using deploy by plugin id with the ms-kubernetes-tools.vscode-kubernetes-tools extension (it has vscode-yaml as extension dependency) and both seem to work

[akosyakov]

@AlexTugarev could you please approve it as well @JPinkney is not an official committer yet, unfortunately, PR can be only merged after the approved by a committer

[AlexTugarev]

The code changes look good to me! 🙏