[FIX] point_of_sale: support non-company currencies
[FIX] point_of_sale: support non-company currencies

Multiple currencies in the same POS have never been
supported. However, before ac89783d2f6cf5477de1c5e576e90ee0f576c9cc it
was possible to load a POS with a currency different from the
company's currency through the sales journal.

This re-introduces that option by manually converting to the default
pricelist currency if it's different from the company currency.

The currency conversion implemented here is based on (and should be
identical to) _convert on res.currency.

opw-1863047

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