Note existing live services in go live ticket

It’s useful for analysing our growth to know if someone who’s requesting
to go live is already a live user of Notify.

app/notify_client/user_api_client.py

@@ -219,6 +219,11 @@ class UserApiClient(NotifyAdminAPIClient):
         ), [])
         return sorted(all_services, key=lambda service: service['name'])
 
+    def user_has_live_services(self, user):
+        return not all(
+            service['restricted'] for service in self.get_services_for_user(user)
+        )
+
     def get_service_ids_for_user(self, user):
         return {
             service['id'] for service in self.get_services_for_user(user)