After all user data has been moved off the config server and all range deletions have finished, transitionToDedicatedConfigServer will locally drop the drained sharded collections on the config server so it can transition back to config shard mode without user intervention (otherwise the transition back would fail because the empty local collections have the same namespace as the real collections in the cluster). If the user has a sharded view (e.g. a time series collection), there may be system.views collections in the same database as a sharded collection, which currently are not dropped and fail subsequent transitionFromDedicatedConfigServer commands. To avoid this, instead of dropping the drained collections, the config server can locally drop any tracked databases (ie with an entry in config.databases, which cannot include config or admin).