[FIX] website_sale: removing invalid product from the cart

Reproduce the issue:
- Install eCommerce app
- Publish a product to your website
- Add the product in your cart
- Unpublish/make unsellable/archive the product

The product is still in the cart and the checkout process can be done.

Cause: There is no check for invalid products before displaying the cart

This commit remove the invalid products while loading the cart.

OPW-2092541

closes odoo/odoo#40168

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>