[FIX] point_of_sale: prevent access error in calling `set_cashbox_pos`

https://github.com/odoo/odoo/pull/112094


after this commit, if a user doesn't have the required access
write to create an account move, the access error will happen during
the set_cashbox_pos calls. It will cause them to not change the
opening amount and the state won't change to open.

opw-3187900

closes odoo/odoo#113091

Signed-off-by: Trinh Jacky (trj) <trj@odoo.com>