No longer sync on successful delete or star operation

[sssoleileraaa]

Description

Now that metadata syncs have been moved to the queue and are top priority, we should no longer call sync_api when it's not necessary. When a source successfully deletes, we should delete the source locally without calling sync_api. When a star successfully is updated, we should untoggle the star (with the current error messaging to the user) without calling sync_api.

[redshiftzero]

To redraw the UI element (e.g. the star) when this change is made, a signal should be emitted to update just the relevant widget (this is one of the reasons why sync_api is being used everywhere).

[ntoll]

OK... I'm looking at this. I've already done the star updating. Onto delete.