[FIX] point_of_sale: allow pos user to open pos with cash control

Have a user [DEMO] with just user permission on POS
Have a POS configured with advanced cash control
With user [DEMO] open POS session

Traceback will occur because [DEMO] cannot access the relevant model

opw-2464150

closes odoo/odoo#67068

Signed-off-by: pimodoo <pimodoo@users.noreply.github.com>