Core/Items: Fixed a possible crash with soulbound tradable items

Closes #15700

(cherry picked from commit 094f505e404b5a4e4846657031f89ac44626a1f8)

src/server/game/Entities/Player/Player.cpp

@@ -13230,36 +13230,25 @@ void Player::TradeCancel(bool sendback)
 
 void Player::UpdateSoulboundTradeItems()
 {
-    if (m_itemSoulboundTradeable.empty())
-        return;
-
     // also checks for garbage data
-    for (ItemDurationList::iterator itr = m_itemSoulboundTradeable.begin(); itr != m_itemSoulboundTradeable.end();)
+    for (GuidUnorderedSet::iterator itr = m_itemSoulboundTradeable.begin(); itr != m_itemSoulboundTradeable.end();)
     {
-        ASSERT(*itr);
-        if ((*itr)->GetOwnerGUID() != GetGUID())
-        {
-            m_itemSoulboundTradeable.erase(itr++);
-            continue;
-        }
-        if ((*itr)->CheckSoulboundTradeExpire())
-        {
-            m_itemSoulboundTradeable.erase(itr++);
-            continue;
-        }
-        ++itr;
+        Item* item = GetItemByGuid(*itr);
+        if (!item || item->GetOwnerGUID() != GetGUID() || item->CheckSoulboundTradeExpire())
+            itr = m_itemSoulboundTradeable.erase(itr);
+        else
+            ++itr;
     }
 }
 
 void Player::AddTradeableItem(Item* item)
 {
-    m_itemSoulboundTradeable.push_back(item);
+    m_itemSoulboundTradeable.insert(item->GetGUID());
 }
 
-/// @todo should never allow an item to be added to m_itemSoulboundTradeable twice
 void Player::RemoveTradeableItem(Item* item)
 {
-    m_itemSoulboundTradeable.remove(item);
+    m_itemSoulboundTradeable.erase(item->GetGUID());
 }
 
 void Player::UpdateItemDuration(uint32 time, bool realtimeonly)

src/server/game/Entities/Player/Player.h

@@ -2392,7 +2392,7 @@ class Player : public Unit, public GridObject<Player>
 
         EnchantDurationList m_enchantDuration;
         ItemDurationList m_itemDuration;
-        ItemDurationList m_itemSoulboundTradeable;
+        GuidUnorderedSet m_itemSoulboundTradeable;
 
         void ResetTimeSync();
         void SendTimeSync();