Remove auto fix worker with migration

What does this MR do and why?

Remove auto fix worker with migration (based on our docs). Follow up from !142046 (merged)

Changelog: removed

Related issue: #435432 (closed)

DB migrate/rollback

$ bundle exec rails db:migrate
main: == [advisory_lock_connection] object_id: 120100, pg_backend_pid: 31216
main: == 20240311101017 RemoveAutoFixWorkerJobs: migrating ==========================
main: -- transaction_open?(nil)
main:    -> 0.0000s
main: == 20240311101017 RemoveAutoFixWorkerJobs: migrated (0.0053s) =================

main: == [advisory_lock_connection] object_id: 120100, pg_backend_pid: 31216

$ bundle exec rails db:migrate:down:main VERSION=20240311101017
main: == [advisory_lock_connection] object_id: 119740, pg_backend_pid: 32461
main: == 20240311101017 RemoveAutoFixWorkerJobs: reverting ==========================
main: == 20240311101017 RemoveAutoFixWorkerJobs: reverted (0.0035s) =================

main: == [advisory_lock_connection] object_id: 119740, pg_backend_pid: 32461

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