Fix missing returns after disconnect in 95179c5e46.

Patch by @elexis.

The package sent in fa85527baf / #2420 plus this missing return causes the NetServerTurnManager
to be stalled forever if a client succeeds to send this package on disconnect.

In NotifyFinishedClientCommands, Disconnect calls OnDisconnect calls UninitialiseClient calls m_ClientsData.erase,
but then m_ClientsData[client].readyTurn = turn; reinserts the disconnected client, making the turnmanager wait forever for the disconnected client.

refs https://wildfiregames.com/forum/topic/134742-bug-game-incredibly-slowfreeze-at-start-because-because-of-1-player/

source/network/NetServerTurnManager.cpp

@@ -69,6 +69,7 @@ void CNetServerTurnManager::NotifyFinishedClientCommands(CNetServerSession& sess
 			m_ClientsData[client].readyTurn + 1);
 
 		session.Disconnect(NDR_INCORRECT_READY_TURN_COMMANDS);
+		return;
 	}
 
 	m_ClientsData[client].readyTurn = turn;
@@ -124,6 +125,7 @@ void CNetServerTurnManager::NotifyFinishedClientUpdate(CNetServerSession& sessio
 			m_ClientsData[client].simulatedTurn + 1);
 
 		session.Disconnect(NDR_INCORRECT_READY_TURN_SIMULATED);
+		return;
 	}
 
 	m_ClientsData[client].simulatedTurn = turn;