Bug 31907: Show items as On hold when in processing

Bug 31907: Show items as On hold when in processing

Test plan:
1. Make sure syspref "opacbookbag" is set to "Allow".
2. Make sure syspref "HoldsNeedProcessingSIP" is set to "Don't fulfill".
3. Place a hold on an item.
4. Return item via SIP at the pickup library.
5. View biblio in Opac.
6. Note that it says "Available" as status.
7. Add biblio to Cart.
8. Open Cart.
9. Note that it says "Available" as status.
10. Apply patch.
11. Reload Opac page.
12. It should now say "On hold".
13. Reload Card page.
14. It should also say "On hold".

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>