Investigate if we can drop ` index_users_with_static_object_token`

As part of reducing lightweight lock contention, investigate if it's possible to drop the index index_users_with_static_object_token from the projects table

• Find out when and why the index was added
• Decide if the index can be dropped
• Drop the index if possible
• If the index cannot be dropped, document the reason in a comment on this issue and close. /copy_metadata #429092 (closed)