[FIX] stock_account: compute price if no product
[FIX] stock_account: compute price if no product

- Activate anglo-saxon accounting
- Create an invoice with a line without product but a UOM
- Validate

A traceback arises since `_compute_price` is called on an empty
recorset.

opw-1830042

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