Bug 29553: Fix crash on undefined notforloan value

Bug 29553: Fix crash on undefined notforloan value

Test plan:
Set item level itypes to biblioitems.
Find a record with itemtype NULL, having an item.
Place a hold. Without this patch, it crashes.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: ThibaudGLT <thibaud.guillot@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit 2eec30eb644bbc6a1851b5264a68c84ee177602e)

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>