Alias bhmagick -> tobias_leviathan

BUR #25839 has been rejected.

create alias bhmagick -> tobias_leviathan

Username artist uses on Bluesky. https://bsky.app/profile/bhmagick.bsky.social

This kind of alias is not very useful, especially if the artist does not actually use the username in their visible display name.

The bulk update request #25839 (forum #279150) has been rejected by @nonamethanks.