Bug 35344: Warn on patron image upload if missing cardnumber

Bug 35344: Warn on patron image upload if missing cardnumber

This change displays a warning message instead of the patron image
upload feature in the patron record when the patron is missing the
cardnumber.

Without this change, the staff user can try to upload a patron image
but it will silently fail. This change warns the staff user of the
cardnumber requirement for patron image upload.

Test plan:
0. Apply the patch
1. Enable the "patronimages" system preference
2. Go to http://localhost:8081/cgi-bin/koha/members/moremember.pl?borrowernumber=51
3. Click "Add" over the patron image placeholder
4. Note the "Upload photo" button and the ability to take a patron photo if your
device has a camera
5. Remove "cardnumber" from BorrowerMandatoryField
6. Go to http://localhost:8081/cgi-bin/koha/circ/circulation.pl?borrowernumber=51
7. Edit the patron to remove the cardnumber
8. Click "Add" over the patron image placeholder
9. Note that no patron image upload features appear. Instead, only
a warning appears stating that the patron needs a cardnumber before
the patron image upload can be performed

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>