indexOneArtist only wrote the artist entry when aliases were non-empty.
Artists without MB aliases (common for smaller/niche artists) never got
an entity_type='artist' row, so indexedArtistMBIDs() couldn't see them.
filterUnindexed then treated them as new on every startup, triggering
redundant LB API calls for top-release-groups and top-recordings.
Now the artist row is always written, with aliases as an empty string
when none exist. Subsequent builds will correctly skip these artists.