[FIX] point_of_sale: change pricelist remove price extra (variant)

Create a product with variants attributes that NEVER create variants.
Configure Variants to add some extra-prices to some variants.
In POS settings activate "Product Configurator" and
"Advanced Pricelists", add the public pricelist and one that applies 5% to
the product.

Open a session and select the product created (say price = 1$)
Select the attributes, the extra-price is added to the product (say the
total price now is 2$).
Change pricelist from public to 5% and the order line will show our
product = 0.95, not taking the extra-prices into account (so not 1.9,
i.e. 5% of the 2$ that were formerly displayed)

opw-2439445

closes odoo/odoo#65222

X-original-commit: 323d2937
Signed-off-by: agr-odoo <agr-odoo@users.noreply.github.com>