Buy X Get Y promotion creates orphaned order items with NULL order_id when using Calculated Formatter

Any chance you could test the patch from the attached MR? This is a completely blind fix.

hm.. Maybe not the right fix...as we have $get_order_items[$order_item->id()] = $order_item; later on... Maybe the whole auto add logic should be bypassed in case an unsaved order is passed?

So I believe with my changes, the BuyXGetY auto add feature won't work when the price calculated formatter invokes the processsor, at the same time, I don't think it makes sense for the formatter to trigger the creation of a new order item that is then orphaned and saved into the DB permanently.