[#73579] Assign actual costs on #update_account

During bulk account reassignment, it's possible for the price group to change. This patch should reassign actual costs when that happens, similar to what happens when updating quantities.

It also adds the requested "cancel" buttons to the bulk reassignment UI.
Yes. Eliminating the `setup_order` helper and swapping in the factory turned out to be more or less a drop-in replacement.