Remove backfill_workspace_personal_access_token_spec
What does this MR do and why?
Removes backfill_workspace_personal_access_token_spec
This spec was related to unusually slow run, and was likely related to underlying database performance problems. Since the BBM is completed, we don't need this spec coverage anymore.
The migration was already finished:
Related #463600 (closed)
Edited by Leonardo da Rosa