[FIX] point_of_sale: use customer language for invoice product

Current behavior:
When creating an invoice from a POS order, the invoice product is not
written in the customers language.

Steps to reproduce:
- Create a customer that uses French as language
- Make sure the user is using English as language
- Create a POS order for the customer
- Invoice the order and look for the product name
- The product name is in English but it should be in French

opw-3283743

closes odoo/odoo#137027

X-original-commit: 1081f7ff670f30e7d69b5e07fb1eb5b2619e3eaa
Signed-off-by: Robin Heinz (rhe) <rhe@odoo.com>
Signed-off-by: Robin Engels (roen) <roen@odoo.com>

addons/point_of_sale/models/pos_order.py

@@ -225,7 +225,8 @@ class PosOrder(models.Model):
             order.add_payment(return_payment_vals)
 
     def _prepare_invoice_line(self, order_line):
-        name = order_line.product_id.get_product_multiline_description_sale()
+        #apply customer language on invoice
+        name = order_line.product_id.with_context(lang=order_line.order_id.partner_id.lang or self.env.user.lang).get_product_multiline_description_sale()
         return {
             'product_id': order_line.product_id.id,
             'quantity': order_line.qty if self.amount_total >= 0 else -order_line.qty,