macosx: Prevent unnecessary reloadData calls in VLCLibraryAudioDataSource

Not only does this prevent wasting resources, it also fixes some bugs such as the sudden closing of the album supplementary view.

With the fixes in this PR:

Screen_Recording_2022-07-20_at_00.38.24

Before the fixes in this PR:

Screen_Recording_2022-07-20_at_00.42.06