[Enhancement] allow support for playlist of all the channel's videos sorted by popularity

[advait404]

Currently, invidious has support for showing the playlist for all videos of a channel, if sorted based on release date. However, there is no way to make it work so that the sorting is done based on the popularity / views. On YouTube, there is only a small change in the URL for a popularity sorted playlist, but adding the URL in invidious does not show the playlist.

eg, when all videos of a channel are in a playlist, sorted based on release date (&list=UU): YouTube link: https://www.youtube.com/watch?v=8YjMIjLLIwA&list=UUXuqSBlHAE6Xw-yeJA0Tunw invidious link: https://yewtu.be/watch?v=8YjMIjLLIwA&list=UUXuqSBlHAE6Xw-yeJA0Tunw

eg, when all videos of a channel are in a playlist, sorted based on popularity (&list=PU): YouTube link: https://www.youtube.com/watch?v=eQ_8F4nzyiw&list=PUXuqSBlHAE6Xw-yeJA0Tunw invidious link: https://yewtu.be/watch?v=eQ_8F4nzyiw&list=PUXuqSBlHAE6Xw-yeJA0Tunw

In the first case, invidious makes a proper playlist. However, in the second case, there is no playlist. This is pretty frustrating for situations when we want to see the best videos of a channel quickly, without opening too many tabs.

[SamantazFox]

It's probably due to PU... playlists being different from regular ones. We'll have to look into that!