Remove bogus C# finalizers (#28315)

Begging people to learn how this programming language works before throwing random syntax into a file.

None of these finalizers ever worked. I also checked whether they were memory leaks and needed *proper* shutdown logic, but they're all instantiated-once UI controls that last for the entire lifetime of the program so it's probably fine.

Content.Client/UserInterface/Systems/Inventory/Controls/ItemSlotButtonContainer.cs

@@ -22,9 +22,4 @@ public sealed class ItemSlotButtonContainer : ItemSlotUIContainer<SlotControl>
     {
         _inventoryController = UserInterfaceManager.GetUIController<InventoryUIController>();
     }
-
-    ~ItemSlotButtonContainer()
-    {
-        _inventoryController.RemoveSlotGroup(SlotGroup);
-    }
 }