Add an icon for build triggers and properly handle build trigger activation errors

endpoints/api.py

@@ -1434,8 +1434,7 @@ def activate_build_trigger(namespace, repository, trigger_uuid):
                                         trigger.auth_token, new_config_dict)
       except TriggerActivationException as e:
         token.delete_instance()
-        abort(400, message = e.msg)
-        return
+        return request_error(message=e.message)
 
       # Save the updated config.
       trigger.config = json.dumps(final_config)