[FIX] stock: no company on customer and supplier
[FIX] stock: no company on customer and supplier

Make sure that the company is not set on the customer and supplier
locations of the demo data. Otherwise, any quant in these locations will
be set a `company_id`, which is incorrect (e.g. valuation report will be
incorrect).

opw-1884835

closes odoo/odoo#27144
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo