[FIX] website_sale: website payment terms issue with portal users

Steps to reproduce the bug:
-create a child contact of a company C
-invite the child contact as a portal user
-sign into the website and place an order w/ wire transfer as payment acquirer

Bug:
The payment term set on the quotation was not taken from the company C and
the default sales person  was not taken from company C too.

opw:745091