refineCollectionShardKey relies on the release of the critical section to clear the filtering collection metadata on primary and secondary nodes, as a safeguard.
In the authoritative model, the release of the critical section will not clear the filtering metadata, as a previous step would have installed the up-to-date version.

As a step towards that goal, we need to first make refineCollectionShardKey use a command to clear the filtering metadata and an oplog c entry, rather than relying on the ShardServerOpObserver on deletion of the critical section document.

This makes it easy to control via a feature flag whether a clear is needed at release time, rather than at insert time.