Add support for downloading live videos more than 4 hours back

[dd-pardal]

The YouTube player allows to go "back in time" in a live video up to 12 hours, and if you pause the video at -12h and return after some time, you can still play it, so it should be possible to download the video even more than 12 hours back.

However, using ytdl-core, I could only download live videos up to 4 hours back, which was the previous limit.