[REV] point_of_sale: allow multiple cash payment methods in PoS

We are reverting this commit (f9da3590) because
it is not compliant to the stable policy and is blocking users that had more than one cash
payment methods in configuring their pos.

opw-3331677

closes odoo/odoo#121959

X-original-commit: e61ceb54
Signed-off-by: Joseph Caburnay (jcb) <jcb@odoo.com>
Signed-off-by: Pedram Bi Ria (pebr) <pebr@odoo.com>