Fix: [Network] clients leaving because of broken connections was not broadcasted (#9238)

The code mixed up "client has quit but we already told everyone"
with "client lost connection, handle this".

Split up those two signals:
- CLIENT_QUIT means we told everyone and the connection is now dead
- CONNECTION_LIST means we should tell everyone we lost a client

src/network/network.cpp

@@ -585,13 +585,13 @@ void NetworkClose(bool close_admins)
 		}
 
 		for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
-			cs->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
+			cs->CloseConnection(NETWORK_RECV_STATUS_CLIENT_QUIT);
 		}
 		ServerNetworkGameSocketHandler::CloseListeners();
 		ServerNetworkAdminSocketHandler::CloseListeners();
 	} else if (MyClient::my_client != nullptr) {
 		MyClient::SendQuit();
-		MyClient::my_client->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
+		MyClient::my_client->CloseConnection(NETWORK_RECV_STATUS_CLIENT_QUIT);
 	}
 
 	TCPConnecter::KillAll();