This change uses _album_for_id and _track_for_id instead of the full
autotag.match.* functions. This should be faster (requiring fewer calls to the
MusicBrainz API) while also being more predictable. It also won't, for
example, use acoustic fingerprinting even if the chroma plugin is installed.
Finally, this change catches the error case in which MBIDs are erroneous. This
can happen, for example, if the user has some track MBIDs left over from
before the NGS transition.