Bug 35108: Hide empty fields on ILL manage request page

Bug 35108: Hide empty fields on ILL manage request page

Optionally empty fields are: orderid, biblio_id, batch,
type, type_disclaimer_value, type_disclaimer_date, cost,
price_paid, notesstaff, notesopac.

Test plan, k-t-d:
1) Install FreeForm and BLDSS backends, run:
bash <(curl -s https://raw.githubusercontent.com/ammopt/koha-ill-dev/master/start-ill-dev-plus.sh)
2) Create a new FreeForm request, visit:
/cgi-bin/koha/ill/ill-requests.pl?method=create&backend=FreeForm
5) Set type 'Book', put '42' in the cardnumber, and pick a library. Click 'create'.
6) Notice how there is a lot of unnecessary empty field entries
7) Apply patch, restart plack (koha-plack --restart kohadev)
8) Refresh the page, notice all the empty fields entries are no longer displayed

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>