fix(DiscoverCenter): 修正内部消息处理逻辑，仅处理消息ID小于0的内部消息

修改消息处理条件，明确只处理NetworkMessagePackage类型且消息ID小于0的内部消息，避免误处理其他类型消息

Author: AlianBlank

GameFrameX.StartUp/DiscoverCenter/GameAppClient.cs

@@ -247,8 +247,8 @@ private void OnClientOnConnected(object client, EventArgs e)
     private void OnClientOnDataReceived(object client, DataEventArgs e)
     {
         var message = MessageHelper.DecoderHandler.Handler(e.Data.ReadBytesValue(e.Offset, e.Length));
-
-        if (message is InnerNetworkMessage innerNetworkMessage)
+        // 只处理内部消息
+        if (message is NetworkMessagePackage innerNetworkMessage && innerNetworkMessage.Header.MessageId < 0)
         {
             _mGameAppClientEvent.OnMessage?.Invoke((MessageObject)innerNetworkMessage.DeserializeMessageObject());
         }