Bug 36612: Add public_read_list to Koha::Ticket

Without the public_read_list to define which fields should be accessible
from the public endpoints we will always return a 500 from the API on
otherwise successfull additions of tickets via the OPAC.

Test plan
1) Enable OPACCatalogConcerns
2) Login to the OPAC and "Report a concern"
3) Note the error message in the UI "There was an error when submitting
   your concern, please contact a librarian."
4) Confirm that the concern is actually created regardless
5) Apply the patch here and restart plack
6) Submit another 'Report a concern' and now note the success message
   "Your concern was successfully submitted."

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 834fc10650)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit d6cf0250a9)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

Koha/Ticket.pm

@@ -168,6 +168,20 @@ sub store {
 
 =cut
 
+=head3 public_read_list
+
+This method returns the list of publicly readable database fields for both API and UI output purposes
+
+=cut
+
+sub public_read_list {
+    return [
+        'ticket_id',   'title',         'body',
+        'reporter_id', 'reported_date', 'resolved_date',
+        'biblio_id'
+    ];
+}
+
 =head3 to_api_mapping
 
 This method returns the mapping for representing a Koha::Ticket object