Core/GameObjects: Allow certain types to be sent to the client without display

Port From (https://github.com/TrinityCore/TrinityCore/commit/6c71a84e6cd980cfe9a35421e8473dceebafba5b)

Source/Game/Entities/GameObject/GameObjectData.cs

@@ -712,6 +712,12 @@ namespace Game.Entities
             }
         }
 
+        public bool IsDisplayMandatory() => type switch
+        {
+            GameObjectTypes.SpellFocus or GameObjectTypes.Multi or GameObjectTypes.SiegeableMulti => false,
+            _ => true
+        };
+        
         public void InitializeQueryData()
         {
             QueryData = new QueryGameObjectResponse();