Bug 23806: FinePaymentAutoPopup does not trigger pop-up for writeoff by "Write off...

Bug 23806: FinePaymentAutoPopup does not trigger pop-up for writeoff by "Write off" button

Test Plan:
1) Enable reciept popups for payments and writeoffs
2) Test the "Write off" button, no popup
3) Apply this patch
4) Restart all the things!
5) Test again, you should get the popup!

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Sean McGarvey <seanm@pascolibraries.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>