Bug 33844: Modify test to show problem

Bug 33844: Modify test to show problem

Add delete key.
Without the follow-up, this triggers a delete. Test fails.
DBIx::Class::Row::delete(): Not in database at /usr/share/koha/Koha/Object.pm line 234

Test plan:
Run t/db_dependent/Koha/Item.t

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>