[FIX] point_of_sale: Add internal product reference to invoice

Current behavior:
The internal product reference is not added to the invoice when the
invoice is created from the POS.

Steps to reproduce:
- Create an order in the POS
- Validate the order and print the invoice
- Open the invoice, the internal product reference is not written on the
  invoice

opw-3119678

closes odoo/odoo#111543

X-original-commit: 38e93f5951528526c060832eecb5514a3ee466a8
Signed-off-by: Engels Robin (roen) <roen@odoo.com>

addons/point_of_sale/models/pos_order.py

@@ -196,7 +196,7 @@ class PosOrder(models.Model):
             'quantity': order_line.qty if self.amount_total >= 0 else -order_line.qty,
             'discount': order_line.discount,
             'price_unit': order_line.price_unit,
-            'name': order_line.full_product_name or order_line.product_id.display_name,
+            'name': order_line.product_id.display_name or order_line.full_product_name,
             'tax_ids': [(6, 0, order_line.tax_ids_after_fiscal_position.ids)],
             'product_uom_id': order_line.product_uom_id.id,
         }