use a2_utils.build_activation_url to create activation URL (#47895)

src/authentic2_auth_fedict/views.py

@@ -64,8 +64,7 @@ class LoginView(mellon.views.LoginView):
             data['valid_email'] = False
             data['skip_email_check'] = True
             data['user_id'] = user.id
-            return HttpResponseRedirect(reverse('registration_activate',
-                    kwargs={'registration_token': signing.dumps(data)}))
+            return HttpResponseRedirect(a2_utils.build_activation_url(request, **data))
         user.is_active = True
         user.save()
         return super(LoginView, self).authenticate(request, login, attributes)