Don't pause a video in AdGuard player when the screen is turned off

### Issue Details

AdGuard is very handy when you want to listen to a podcast or an hour+ long music video. But after you turn off your screen the player pauses the video.

### Proposed solution

Add a feature that would allow you to select whether the player should continue playing with the screen off.

### Alternative solution

Make the player continue playing with the screen off by default.