Added 2 secs delay as fix of bug - when volume indicator is show after login

What's the reason for using a timeout like that instead of the `idle_add()` you're already using? As mentioned before, using `idle_add()` is sufficient to access an async property. In enable, you simply need to call `this._queueHideVolumeIndicator()`. If `_volumeOutput` returns after `hide()` is called, the timeout won't help. You need to look at the `_shouldBeVisible()` in `ui/status/volume.js` and either monkey patch it or hide the `_volumeOutput` when it's shown (via the show signal). Anyway, if you wanna use that timeout, it should be removed on disable (line 20 `extension.js`): [EGO Review Guidelines: Timeout](https://gjs.guide/extensions/review-guidelines/review-guidelines.html#remove-main-loop-sources)

Thanks for the suggestions, I'm new in JS and generally in programming, so I can make stupid mistakes... I will try to fix this, meow