Background migrations removed in 17.1 cause upgrade issues

Reported at #431134 (comment 2011150394) some customers are having some issues upgrading to 17.1.2 without going through 17.0 first. This seems like a valid upgrade path based on https://docs.gitlab.com/ee/update/index.html#upgrade-paths .

Per the report:

We found that the finalization of those 2 migrations are actually finalized in 17.0 and removed in 17.1

I think that we shouldn't have been allowed to remove this background migration until after the next required stop which follows when it was finalized. Which according to those docs has not happened yet. So I think I'm inclined to agree that we should not have removed MigrateVulnerabilitiesFeedbackToVulnerabilitiesStateTransition yet.

Related errors

uninitialized constant Gitlab::BackgroundMigration::MigrateVulnerabilitiesFeedbackToVulnerabilitiesStateTransition

uninitialized constant Gitlab::BackgroundMigration::CreateVulnerabilityLinks