Since SERVER-102024, a mongod process has to always honor the write concern attached to an incoming request before returning a response.

This change now requires shardCollection requests to have their write concern upgraded to 'majority' before the mongos node forwards them to the primary shard, instead of just doing that within the context of the DDLCoordinator - or the primary shard could raise an UnsatisfiableWriteConcern error when applying the received parameter upon command completion.