Fix bug in album track listing

[mikey-austin]

Trying to list the tracks in an album borks with this stack trace:

   ERROR    [HttpServer] mopidy_iris.handlers local variable 'data' referenced before assignment
   ERROR    [YTMusicBackend-3 (_actor_loop)] mopidy_ytmusic YTMusic failed getting tracks for album "xxx"
   Traceback (most recent call last):
     File "/usr/local/lib/python3.10/dist-packages/mopidy_ytmusic/library.py", line 437, in lookup
       tracks = self.albumToTracks(res, bId)
     File "/usr/local/lib/python3.10/dist-packages/mopidy_ytmusic/library.py", line 904, in albumToTracks
       songartists = [Artist(name=song["artists"])]
     File "/usr/lib/python3/dist-packages/mopidy/models/immutable.py", line 159, in __call__
       instance = super().__call__(*args, **kwargs)
     File "/usr/lib/python3/dist-packages/mopidy/models/immutable.py", line 35, in __init__
         self._set_field(key, value)
     File "/usr/lib/python3/dist-packages/mopidy/models/immutable.py", line 188, in _set_field
       object.__setattr__(self, name, value)
     File "/usr/lib/python3/dist-packages/mopidy/models/fields.py", line 50, in __set__
       value = self.validate(value)
     File "/usr/lib/python3/dist-packages/mopidy/models/fields.py", line 34, in validate
       raise TypeError(
     TypeError: Expected name to be a <class 'str'>, not [{'name': 'blah', 'id': None}]

This was an apparent typo since the type validation clearly expects a
string and not the full Artist object.

[mikey-austin]

Fixes #63

[mikey-austin]

Fixes #39

[rebernet]

Thanks for the fix. Finally I am able to load the tracks of an album (built and installed from your branch). Please merge.

[GhoulBoii]

@impliedchaos Sorry for the ping but can this be merged? This fixes #39, #38 and #63. It also removes the need of pr's #62 and #55 i think.

[impliedchaos]

No worries on the ping, apparently I needed it. I'll get this merged and push out a new bugfix release ASAP.