Requeue backfill migration for remediations
This MR introduces a post-deployment migration to reschedule a background job to backfill remediations in vulnerability_reads
table. There was a failed attempt to reschedule this migration !135747 (merged) where a step to delete original migration was not present.
Followed the step from doc: https://docs.gitlab.com/ee/development/database/batched_background_migrations.html#re-queue-batched-background-migrations
Related to #429361 (closed)
Edited by Subashis Chakraborty