New implementation of sales channels (#4111)

Co-authored-by: Martin Gross <gross@rami.io>

src/pretix/control/views/pdf.py

@@ -98,6 +98,7 @@ class BaseEditorView(EventPermissionRequiredMixin, TemplateView):
         from pretix.base.models import Order
         order = self.request.event.orders.create(status=Order.STATUS_PENDING, datetime=now(),
                                                  email='sample@pretix.eu',
+                                                 sales_channel=self.request.event.organizer.sales_channels.get(identifier="web"),
                                                  locale=self.request.event.settings.locale,
                                                  expires=now(), code="PREVIEW1234", total=Decimal('119.00'))