fix: allow all listener to be executed for AsyncEmitter

[Maddobun]

What it does

With AsyncEmitters, if a listener callback does not call event.waitUntil, other listeners that are registered after this one will fail to be called due to early loop termination.

How to test

Register two separate callbacks without waitUntil for FileService.onDidRunUserOperation or any other AsyncEmitter.event and fire an event. Verify that both callbacks are called correctly.

Review checklist

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

Reminder for reviewers

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[tortmayr]

Thanks! Looks good to me.
AsyncEmitters now work as expected and all listener callback are invoked when an event is fired even if some of them don't use Event.waitUntil in the callback.
Nice catch!

[JonasHelming]

@tortmayr Thank you for the reivew, do you want to merge?