fix : 패킷 Vector3 -> Position 변경 (유니티 호환성)

ClientTester/EchoClientTester/StressTest/StressTestClient.cs

@@ -152,7 +152,7 @@ public class StressTestClient
         {
             PlayerId = clientId,
             RotY = rotY,
-            Position = new Packet.Vector3 { X = position.X, Y = 0, Z = position.Z }
+            Position = new Packet.Position { X = position.X, Y = 0, Z = position.Z }
         };
         byte[] data = PacketSerializer.Serialize((ushort)PacketCode.TRANSFORM_PLAYER, pkt);
         writer.Put(data);