Core/Items: Prevent swapping item sets while player is in combat

src/server/game/Server/Protocol/Handlers/CharacterHandler.cpp

@@ -1401,6 +1401,9 @@ void WorldSession::HandleEquipmentSetDelete(WorldPacket &recv_data)
 
 void WorldSession::HandleEquipmentSetUse(WorldPacket &recv_data)
 {
+    if (_player->isInCombat())
+        return;
+
     sLog->outDebug(LOG_FILTER_NETWORKIO, "CMSG_EQUIPMENT_SET_USE");
     recv_data.hexlike();