Bankimport: Add a delay before starting the background task

src/pretix/plugins/banktransfer/views.py

@@ -327,7 +327,7 @@ class ImportView(EventPermissionRequiredMixin, ListView):
             'event': self.request.event.pk,
             'job': job.pk,
             'data': parsed
-        })
+        }, countdown=1)
         return redirect(reverse('plugins:banktransfer:import.job', kwargs={
             'event': self.request.event.slug,
             'organizer': self.request.event.organizer.slug,