[SoundCloud] Fix certain playlists showing as empty

[petlyh]

• I carefully read the contribution guidelines and agree to them.
• I have tested the API against NewPipe.
• I agree to create a pull request for NewPipe as soon as possible to make it compatible with the changed API.
  No NewPipe changes required.

For certain SoundCloud playlists, the initial playlist data does not include the full track info for any of the tracks. Because of this, no items get collected in getIntialPage and NewPipe shows the playlist as empty.

This change makes it so that getPage is used in initial extraction in those cases to prevent getInitialPage from returning no items.

I have tested that other playlists still work, including actually empty ones.

Fixes TeamNewPipe/NewPipe#10012

Before	After

[Stypox]

This should be changed on NewPipe's side. I just tested and the following commit from TeamNewPipe/NewPipe#10018 fixes the issue: TeamNewPipe/NewPipe@e236d37