list onFileSystem activation event as supported

[akosyakov]

What it does

• fix Unsupported activation events: onFileSystem:git #8319: list onFileSystem activation event as supported

How to test

• install git built-in extension from Extensions view and check that logs don't contain unsupported activation events: onFileSystem:git
  • extension does not work, but it is not the point of this PR: vscode git built-in extension (1.47.3) does not work #8318

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

[AlexTugarev]

@typescript-eslint/eslint-plugin cannot be found, i.e. the build is broken. 'will revisit later.

[RomanNikitenko]

@akosyakov
Tested for master branch and current PR branch, can confirm, that

• for master branch I can see:
  
  at adding git built-in extension

• I don't see such log using current PR changes

• I still see the notification:

But I guess it's OK for current PR and according to the PR description will be fixed within #8318