[FIX] event_sale: canceled registrations

- Open an event registration page
- Fill form for 2 persons => redirection to /shop/checkout
- Click Review Order => open /shop/cart
- Change quantity from 2 to 1
- Finish checkout process
- Login to backend, confirm SO

Two tickets are confirmed instead of one.

opw-783945

addons/event_sale/models/sale_order.py

@@ -41,7 +41,7 @@ class SaleOrderLine(models.Model):
         registrations linked to this line. This method update existing registrations
         and create new one for missing one. """
         Registration = self.env['event.registration']
-        registrations = Registration.search([('sale_order_line_id', 'in', self.ids)])
+        registrations = Registration.search([('sale_order_line_id', 'in', self.ids), ('state', '!=', 'cancel')])
         for so_line in self.filtered('event_id'):
             existing_registrations = registrations.filtered(lambda self: self.sale_order_line_id.id == so_line.id)
             if confirm: