Core/PacketIO: Fixed receiving and sending db2 hotfix packets

Port From (https://github.com/TrinityCore/TrinityCore/commit/5fce3604fc9613299f8780d30abbbe69c0c7e531)

Source/Game/Network/Packet.cs

@@ -240,6 +240,6 @@ namespace Game.Network
             byteBuffer.WriteBytes(Tag, 12);
         }
 
-        public bool IsValidSize() { return Size < 0x10000; }
+        public bool IsValidSize() { return Size < 0x40000; }
     }
 }