Grafana edge-app, when it cannot fetch a photo, should show a descriptive error message

We're trying to connect our Grafana to Screenly using the app, but it doesn't work due to an issue with the screenshot API. 
If there is a problem with the screenshot API, the Grafana app should display a descriptive error message in debug mode. 

<img width="4032" height="3024" alt="Image" src="https://github.com/user-attachments/assets/85f7b216-c5b3-42c9-a4e4-6170eec75abf" />