Add a "sorted" option in bulk-update backend to sort updated registrations by payment timestamp

[dunkOnIT]

Offshoot of #10781 - in the long run, we want to be doing the data sorting in the backend not the frontend. However, it will yield some considerations around where and how to load registration and payment data so that it is available for sorting before the update call is made (currently we are only loading the registration in the update function, so the controller doesn't have the data it needs to sort them)