Bug 35862: Fix patron_search_form selection

Bug 35862: Fix patron_search_form selection

We were no longer getting a match here and so ended up with 2 forms on
the budget page (where we have two modals for patron: owner and users).

Caught be selenium tests patrons_search.t :
Error while executing command: element not interactable: Element <a class="patron_name patron_preview" href="/cgi-bin/koha/circ/circulation.pl?borrowernumber=511"> could not be scrolled into view

It fixes the following UI issues:
When you open a modal, start a search, close the modal
open the other modal search: the results from the other modal were shown

Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>