Microphone Access

The [first part](https://huggingface.co/learn/audio-course/chapter0/introduction) includes an iframe, but the microphone access isn't allowed for some reason (I tried in Firefox, Chrome and Firefox mobile).
After like two hours of trying to fix browser permissions and stuff, I finally solved this by opening the frame in a new tab and then the browser permission dialog appeared and I allowed it. However, I guess this will be confusing for other people, so I suggest adding a button to open the demo in a new tab or some notice about this.

(Sorry if it's not the correct repo to report this. I'm new to huggingface 🙂)

Start with the first part of the Audio Course at the linked introduction page and inspect the embedded iframe and its microphone-permission behavior. Reproduce the issue in the browsers mentioned, then verify that the course clearly offers a way to open the demo in a new tab or explains the permission requirement.

Written by the indexing model from the issue text.