Bug 37263: Fix deletion of 'All' patron category in Default article request fees

Bug 37263: Fix deletion of 'All' patron category in Default article request fees

Follow same test plan as before, but attempt to delete a 'All' entry in 'Default article request fees'.
Notice it blows up before this patch. It works as expected after the patch.

Signed-off-by: Roman Dolny <roman.dolny@jezuici.pl>
Signed-off-by: Emmi Takkinen <emmi.takkinen@koha-suomi.fi>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>