Bug 38293: (alternate) Fix setting branch-level JS and CSS

Bug 38293: (alternate) Fix setting branch-level JS and CSS

Test plan:
1. Apply the patch
2. Go to http://localhost:8081/cgi-bin/koha/admin/branches.pl?op=add_form&branchcode=CPL
3. Scroll to bottom of the page and click "Edit" then "Collapse" next
   to Specific OPAC JS and Specific OPAC CSS

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Emily Lamancusa <emily.lamancusa@montgomerycountymd.gov>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>