Bug 21032: Fix using facet for searches made on specific index

Bug 21032: Fix using facet for searches made on specific index

Test plan:

  - Try a simple search (OPAC or staff) like "title:foo",
  - click on a facet: badaboum!
  - apply this patch,
  - retry

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 96f253d5ed2f1770b42f06554ebb4c4e14b3afdf)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit 8cfacd7e164178828b0e75743e78d1740ab414b9)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>