Fix: crash to desktop when attempting to join a company while not joined (yet)

src/network/network.cpp

@@ -798,6 +798,7 @@ public:
 		Debug(net, 9, "Client::OnConnect(): connection_string={}", this->connection_string);
 
 		_networking = true;
+		_network_own_client_id = ClientID{};
 		new ClientNetworkGameSocketHandler(s, this->connection_string);
 		IConsoleCmdExec("exec scripts/on_client.scr 0");
 		NetworkClient_Connected();