Bug 35094: Update batch to ill_batch accessor in .tt file

Bug 35094: Update batch to ill_batch accessor in .tt file

Test plan:
1) Install FreeForm and enable ILLmodule, run:
bash <(curl -s https://raw.githubusercontent.com/ammopt/koha-ill-dev/master/start-ill-dev.sh)
2) Visit /cgi-bin/koha/ill/ill-requests.pl
3) Create 'New ILL request'
4) Select the request type, input cardnumber '42' and select a library
5) Hit 'Create'
6) Notice the request now creates successfully

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>