Bug 35578: Validate "Where" in OPAC Authority search

Bug 35578: Validate "Where" in OPAC Authority search

This patch adds validation to the "Where" field in OPAC Authority search.

Test plan:
0. Apply the patch and koha-plack --reload kohadev
1. Go to http://localhost:8080/cgi-bin/koha/opac-authorities-home.pl
2. Type "test" into "Term(s)" field
3. Click "Submit"
4. Confirm a result is found

5. Repeat the above using "Where" values of "in the complete record",
"in any heading", and "in main entry"

6. Using the HTML inspector in the browser, change the value of
the selected option of the "marclist" select element to
"this is broken"
7. Click "Submit"
8. Confirm a result is found (ie it's not throwing a fatal error
anymore)

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