Safely assigns queued_migration_version on BBM enqueue

...ue_delete_invalid_protected_branch_merge_access_levels.rb

...eue_delete_invalid_protected_branch_push_access_levels.rb

...ueue_delete_invalid_protected_tag_create_access_levels.rb

...20231030071209_queue_backfill_packages_tags_project_id.rb

...14043522_queue_backfill_merge_request_diffs_project_id.rb

...ueue2_backfill_has_remediations_of_vulnerability_reads.rb

doc/development/database/batched_background_migrations.md

doc/development/database/not_null_constraints.md

...ion/templates/queue_batched_background_migration.template

...tabase/migrations/batched_background_migration_helpers.rb

...d_migration/expected_files/queue_my_batched_migration.txt

...e/migrations/batched_background_migration_helpers_spec.rb