GroupDestroyWorker failure - merge_request_diff_commits statement timeout

Summary

Related to &7171

On Gitlab.com, GroupDestroyWorker sometimes fails due to a non-deleteable project. The failures are tracked in this Kibana dashboard.

We have narrowed down the failures to ten distinct Project#delete_error values. This issue deals with project deletion errors due to

PG::QueryCanceled: ERROR:  canceling statement due to statement timeout
CONTEXT:  SQL statement "DELETE FROM ONLY "public"."merge_request_diff_commits" WHERE $1 OPERATOR(pg_catalog.=) "merge_request_diff_id""

The full list of delete_errors can be found here: https://gitlab.com/gitlab-org/gitlab/-/issues/342692#note_737332055

Impact

In the past week, GroupDestroyWorker has failed ~1500 times due to 138 projects attempting to be deleted over and over again.

Recommendation

Verification