Bug 24611: Fix wrong budget_id query param in /acquisitions/orders

Bug 24611: Fix wrong budget_id query param in /acquisitions/orders

This patch fixes the wrong query parameter that slipped on rewriting the
patches for the voted RFC.

To test:
1. Apply the tests patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/api/v1/acquisitions_orders.t
=> FAIL: Tests fail because fund_id is not a valid query parameter
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: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>