Revert "Bug 22478: (QA follow-up) Handle category in opac-shelves like a boolean"

Revert "Bug 22478: (QA follow-up) Handle category in opac-shelves like a boolean"

This reverts commit 375dd35d5354d46c4c16f534494b123ce370c3f4.

https://bugs.koha-community.org/show_bug.cgi?id=22836
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 7bed2a3fe61ff605b636e292e73b96947de23b29)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>