Add check for empty album and handle them gracefully

[arsaboo]

Description

Fixes #5540 (comment)

• Changelog. (Add an entry to docs/changelog.rst to the bottom of one of the lists near the top of the document.)
• Tests. (Very much encouraged but not strictly required.)

[arsaboo]

@snejus I tested this and can confirm that it works.

[snejus]

I'm now thinking: how come do you have empty albums in your library? 😅

[arsaboo]

Haha...I wish I knew 😜

[Serene-Arc]

Perhaps we should add a function to beet update to purge these empty albums? We use the update command to do a lot of cleanup and other functions, so this might be good to fold in. Is there a reason we'd want to keep empty albums in a library database?

[snejus]

Is there a reason we'd want to keep empty albums in a library database?

Definitely not. The funny thing here is that beets never ends up adding empty albums in the first place. The only times I've come across empty albums in my library have been when this happened due to some funky adjustments I made in the source. Could this potentially be the reason why you have them as well @arsaboo?

[arsaboo]

Indeed, it's quite possible those empty albums were created during one of my many tests. We can close this PR for now. If it's comes back again, we can remove the empty albums (which may be a better solution). Unfortunately, I am unable to reproduce it right now to fix it.