add res.apiv3({})

src/server/routes/apiv3/slack-integration-settings.js

@@ -514,6 +514,7 @@ module.exports = (crowi) => {
         channel,
         text: 'Your test was successful!',
       });
+      return res.apiv3({ });
     }
     catch (error) {
       logger.error('Error', error);