[FIX] website_sale: Payment terms in multi companies

Steps to reproduce the bug:

- Let's consider two companies C1, C2 and a website W1 in C1
- Set C2 on the payment term Immediate payment
- Go to the shop
- Add a product in the cart

Bug:

A traceback was raised because Immediate was not in company C1

opw:2431705

closes odoo/odoo#65045

Signed-off-by: Simon Goffin (sig) <sig@openerp.com>