Issue #3610013: List the order's payments on the delete-confirmation screen

The order-delete confirmation lists what the delete will purge (booking lines, the workflow instance) but not the payments, even though BookingPaymentHooks::purgePaymentsOnDelete already removes every payment whose subject is the transaction. This adds the missing line.

A TransactionPayments service finds the payments belonging to a transaction (by subject); purgePaymentsOnDelete deletes through it and a new PaymentCascadeDescriber counts through it, so the number on the screen matches exactly what the delete removes (checkout, deposit and no-show alike).

Kernel test and French translation added. Tests green.