iPhone switches to full screen video preview when entering recording step and when starting to record

[LukasKalbertodt]

I couldn't confirm this yet (as I do not currently have access to an iPhone), but I was shown the following unwanted behavior.

On an iPhone, in Safari, when the user enters the third step (recording page), the video element on the page is shown in full screen mode. The user has to manually quit that mode to see the normal page. The same happens when the user then starts to record.

We do not tell the browser to switch into fullscreen mode. So Safari probably guesses that this is what the user most likely wants. We need to find out how to avoid this behavior.

Also, the preview, if not in fullscreen, is just black.

[LukasKalbertodt]

Solved by #1069