[FIX] pos_coupon: allow coupon creation when generated from POS

When a coupon is generated from POS order, you get a traceback saying
you don't have access rights on "coupon.coupon" when you are only a pos
user.

So when we need to create the coupons and write on it, we are doing it
in sudo, to let the pos process generate the coupon.

Task-id: 2742528
X-original-commit: 2faefd5d6e69170a49c2cc5aca000f791f40f448
Part-of: odoo/odoo#84583

addons/pos_coupon/models/pos_order.py

@@ -39,7 +39,7 @@ class PosOrder(models.Model):
         unused_coupon_ids = unused_coupon_ids or []
 
         self.env["coupon.coupon"].browse(unused_coupon_ids).write({"state": "new"})
-        self.write(
+        self.sudo().write(
             {
                 "applied_program_ids": [(4, i) for i in self.lines.program_id.ids],
                 "used_coupon_ids": [(4, i) for i in self.lines.coupon_id.ids],
@@ -48,7 +48,7 @@ class PosOrder(models.Model):
                     for i in (
                         self.env["coupon.program"]
                         .browse(program_ids_to_generate_coupons)
-                        ._generate_coupons(self.partner_id.id)
+                        .sudo()._generate_coupons(self.partner_id.id)
                     ).ids
                 ],
             }