[FIX] point_of_sale: force no-tax on demo product
[FIX] point_of_sale: force no-tax on demo product

The javascript tour (test) will verify the total amount based on sale
price of the product without taking taxes into account.
However, if any l10n_* module is installed and defined a default value
for product taxes, the test will fail this check.

ygol/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,hip-odoo/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,dfang/odoo,hip-odoo/odoo,ygol/odoo,hip-odoo/odoo,dfang/odoo,dfang/odoo,ygol/odoo,dfang/odoo,ygol/odoo