Core/Objects: Fixed trap visibility for enemies. (#18815)

Closes #18251

src/server/game/Entities/Object/Object.cpp

@@ -1902,7 +1902,7 @@ bool WorldObject::CanDetectStealthOf(WorldObject const* obj, bool checkAlert) co
     if (!HasInArc(float(M_PI), obj))
         return false;
 
-    GameObject const* go = ToGameObject();
+    GameObject const* go = obj->ToGameObject();
     for (uint32 i = 0; i < TOTAL_STEALTH_TYPES; ++i)
     {
         if (!(obj->m_stealth.GetFlags() & (1 << i)))