[FIX] pos_discount: change customer
[FIX] pos_discount: change customer

- Enable general discounts for POS
- Create a POS session
- Add a product
- Create a general discount of 10%
- Change the customer

The discount is reset to the product price.

When changing the customer, the prices are reset:

https://github.com/odoo/odoo/blob/3b1699e02d4483913159681bf7e10839e6493244/addons/point_of_sale/static/src/js/screens.js#L1251

In the case of a global discount, the price is therefore reset to the
product price in:

https://github.com/odoo/odoo/blob/3b1699e02d4483913159681bf7e10839e6493244/addons/point_of_sale/static/src/js/models.js#L2304

To avoid this, we set the price as manually set. Conceptually, this is
indeed the case since we manually chose the percentage, therefore the
price.

opw-2009761

closes odoo/odoo#34418

Signed-off-by: Nicolas Martinelli (nim) <771435c469f83f6aa9c405ac5e1ed06314a94f2d@odoo.com>
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo