Fix FileResource not adding event listener to the disposable collection

[Hanksha]

What it does

This PR fixes the constructor of FileResource so the listener of this.fileService.onDidChangeFileSystemProviderReadOnlyMessage is properly disposed when the resource is disposed.

Fixes #13877

How to test

You can run the playwright test in examples\playwright\src\tests\theia-application-shell.test.ts. Check the logs, you should not see any emitter memory leak warning related to onDidChangeFileSystemProviderReadOnlyMessage event.

Review checklist

• [x] 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

[JonasHelming]

@tsmaeder I think you can merge this one!