Bug 34024: Block changing pickup location for found holds

Bug 34024: Block changing pickup location for found holds

This patch adds a check on holds for 'found' statuses. Holds with the
following statuses have special workflows in Koha, and overwritting
their pickup locations yields uncertain scenarios:

* Waiting: the item has probably been put on a special shelve
* In transit: the item is travelling to a new destination, and changing
  the pickup location should include some validations, and probably
  generate some notifications. At least.
* In processing: the item has already been taken out of the shelve for
  some internal processing. Changing the pickup location could interfere
  with this workflow. Overriding this limitation could be introduced
  with care on a separate report.

To test:
1. Apply the unit tests patch
2. Run:
   $ ktd --shell
  k$ prove t/db_dependent/api/v1/holds.t
=> FAIL: Tests don't pass. Holds go through (200) instead of being
rejected (409).
3. Apply this patch
4. Repeat 2
=> SUCCESS: Tests pass!
5. Sign off :-D

Signed-off-by: Sam Lau <samalau@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>