[FIX] point_of_sale: wrong field name used in constraint

Wrongly defined in #55525

Fixes #82834

closes odoo/odoo#82907

X-original-commit: 6ece16fbb0ceaced022a2d1b3f0c5769ba827125
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>

addons/point_of_sale/models/pos_config.py

@@ -282,7 +282,7 @@ class PosConfig(models.Model):
         for config in self:
             if config.cash_rounding and config.rounding_method.strategy != 'add_invoice_line':
                 selection_value = "Add a rounding line"
-                for key, val in self.env["account.cash.rounding"]._fields["stategy"]._description_selection(config.env):
+                for key, val in self.env["account.cash.rounding"]._fields["strategy"]._description_selection(config.env):
                     if key == "add_invoice_line":
                         selection_value = val
                         break