SERVER-60834 added a barrier on setFCV after which it is guaranteed that no migrations are ongoing still using the old (on upgrade) or new (on downgrade) migration protocol. This barrier is implemented using the MigrationBlockingGuard. However, this is not enough to ensure that there are no migrations pending recovery (which no longer hold the ActiveMigrationRegistry).

This ticket is to ensure that after this barrier, any migration pending recovery has also completed.