fix(server): DOES_PLAYER_EXIST with TempIDs

After 50637e5, DOES_PLAYER_EXIST would
return true for TempIDs belonging to an already-connected player, which
would be a compatibility break.

Since the other fix (TempIDs being invalidated after connection, which
would've been intended behavior) was also a compatibility break, we'll
check for the NetID matching instead.

code/components/citizen-server-impl/src/PlayerScriptFunctions.cpp

@@ -32,7 +32,9 @@ static void CreatePlayerCommands()
 
 	fx::ScriptEngine::RegisterNativeHandler("DOES_PLAYER_EXIST", MakeClientFunction([](fx::ScriptContext& context, const fx::ClientSharedPtr& client)
 	{
-		return true;
+		auto matchID = atoi(context.CheckArgument<const char*>(0));
+
+		return client->GetNetId() == matchID;
 	}));
 
 	fx::ScriptEngine::RegisterNativeHandler("GET_PLAYER_GUID", MakeClientFunction([](fx::ScriptContext& context, const fx::ClientSharedPtr& client)