Bug 35167: Make 'effective_not_for_loan_status' fallback to 0 if itype has it undef

Bug 35167: Make 'effective_not_for_loan_status' fallback to 0 if itype has it undef

This patch makes the effective not for loan status be set the item value
if not defined at itype level.

To test:
1. Apply the regressions tests patch
2. Run:
   $ ktd --shell
  k$ prove t/db_dependent/api/v1/items.t
=> FAIL: Tests fail!
3. Apply this patch
4. Repeat 2
=> SUCCESS: Tests pass!
5. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>