Worker publication: Catch and handle revision_url issues

When publishing a tagged worker version, a worker version with the same revision already exists (pushed through pipeline on the source branch). Arkindex doesn't automatically update the worker version with the tag. The command should handle that part.

Catch errors that match {'revision_url': ['A version already exists for this worker with this revision_url.']}. In that case, call PartialUpdateWorkerVersion with tag (only this field should be updated), only if it's set. Raise the exception in any other case.