lingo: move error message to PayView (#47477)

combo/apps/lingo/views.py

@@ -481,6 +481,12 @@ class PayView(PayMixin, View):
             regie.compute_extra_fees(user=user)
             items = BasketItem.get_items_to_be_paid(user=user).filter(regie=regie)
 
+            if regie.can_pay_only_one_basket_item and len(items) > 1:
+                messages.error(request, _('Grouping basket items is not allowed.'))
+                logger.error('lingo: regie can only pay one basket item, but handle_payment() received',
+                             extra={'regie': str(regie), 'items': items, 'remote_items': remote_items})
+                return HttpResponseRedirect(next_url)
+
         if items:
             capture_date = items[0].capture_date
             for item in items: