Default enable invalid metadata cleaning in background verifier
Metadata records that indicate a replica exists where one doesn't causes issues for Praefect. They may lead to misrouting requests to non-existent replicas and to not upholding the replication factor of a repository. Praefect contains a background verifier that scans the storages periodically and can remove metadata that points to non-existent replicas. This allows Praefect to realize the replicas are missing and re-replicate them and to stop routing requests to non-existent replicas.
The functionality to delete the invalid metadata is currently turned off due to races with repository renames that can lead to data loss. The racy behavior has been fixed and is being rolled out with a feature flag. Once the feature flag is removed, we can default enable the clean up behavior.