[FIX] website_helpdesk_form: adapt code for new xmlid format
[FIX] website_helpdesk_form: adapt code for new xmlid format

Followup of odoo/odoo@0c261df33d1401d236b99213d3cd7a9fa0298a78

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo