Context: diagnosticDataCollectionDirectorySizeMB default is doubled for sharded clusters. There is a test library function verifyCommonFTDCParameters that supposely verify this case, however, none of the existing tests that uses it operates on sharded clusters it (see ftdc_params.js)) or test the mongod
instead of the mongos that won't have the parameter doubled (see ftdc_on_mongos.js).

Objective: Write tests that verify that diagnosticDataCollectionDirectorySizeMB is doubled for sharded clusters.

Notes:

• After SERVER-103231 the default value for stand along clusters is 250 MB and 500 MB for sharded clsuters.
• There seems to be a bug on verifyCommonFTDCParameters on this if statement since the only way findConnectedNodes returns Topology.kShardedCluster is when accessed via mongos (see here, so the condition will never be true.