Remove review summaries table
What does this MR do and why?
We have removed the backend and frontend code in !156646 (merged) and now need to remove the table to finish the removal.
However, we started backfilling in: !156319 (merged)
https://docs.gitlab.com/ee/development/migration_style_guide.html#dropping-a-database-table
Related to #454150
Edited by Marc Shaw