[FIX] point_of_sale: also clone orderline price
[FIX] point_of_sale: also clone orderline price

Otherwise during e.g. bill splitting of an orderline which had it's
price overridden you end up with the original price again.

Fixes #17810
Closes #17811

ygol/odoo,Elico-Corp/odoo_OCB,ygol/odoo,ygol/odoo,ygol/odoo,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,ygol/odoo,ygol/odoo,ygol/odoo,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB