Adding variant to cart sets price to zero when template product's list_price is zero

[elsguns]

Impacted versions: 13

Steps to reproduce:
1/ Create a product with variants.
2/ Set different prices for the variants on the public pricelist.
2/ Set Sales price of product template to zero.

Current behavior:
The price of the variants is displayed correctly on the product page. It becomes zero though when adding it to the cart.

Expected behavior:
Prices for the variant set on the public pricelist should be kept in the cart.

Video/Screenshot link (optional):

Support ticket number submitted via odoo.com/help (optional):

Code that's causing this is website_sale/models/sale_order.py > _website_product_id_change > line 113 > if pu != 0: