Grafana panel keep loading

### Steps to reproduce

1. I added some Grafana widget to my room, and it keep loading without any useful response
2.

3.

I have made sure that the panel can be visited anonymously and my grafana is allow_embedding

### Outcome

#### What did you expect?
at least showing my panel
#### What happened instead?
keep loading without an end

### Operating system

macOS

### Application version

1.11.0

### How did you install the app?

https://element.io/get-started

### Homeserver

matrix.org

### Will you send logs?

Yes