[FIX] point_of_sale: Display the correct discount name in paid orders

Before this commit, the discount name in the paid orders was different
from the one displayed when creating the order. This was due to the
fact that the `full_product_name` field was not being sent to the point
of sale, so the discount product name was being used instead.

This commit fixes the issue by ensuring that the `full_product_name`
field is sent to the point of sale, which allows for the correct discount
name to be displayed in the order menu.

opw-3213225

closes odoo/odoo#116473

X-original-commit: 8df45f2b50f01a9312a2513f39b467583d735a1d
Signed-off-by: Trinh Jacky (trj) <trj@odoo.com>
Signed-off-by: Pedram Bi Ria (pebr) <pebr@odoo.com>

addons/point_of_sale/models/pos_order.py

@@ -1427,6 +1427,7 @@ class PosOrderLine(models.Model):
             'customer_note': orderline.customer_note,
             'refunded_qty': orderline.refunded_qty,
             'price_extra': orderline.price_extra,
+            'full_product_name': orderline.full_product_name,
         }
 
     def export_for_ui(self):