SERVER-103709 refactored DatabaseShardingState (DSS) into an interface intended for use by the shard_role API.

As such, DSS should provide a clear and well-defined API for validating the received dbVersion against the currently installed metadata (also referred to as the "wanted" dbVersion).

It should not expose internal attributes like dbVersion directly, as doing so allows external users to bypass the intended interface and potentially re-implement database version checks at higher layers, which undermines encapsulation and consistency.