[SoundCloud] Tracks like count extraction is broken

[AudricV]

According to 306e31a, SoundCloud was using for the likes count property, the name favoritings_count, and before this name, likes_count.

SoundCloud is currently using likes_count to return the like count of a track.

I don't know since when this change has been made, because I didn't see a report about this bug until today (on the NewPipe subreddit, in a post comment) (edit: it wasn't about these likes, but instead about the likes of a SoundCloud account).

This is an easy fix, and like count tests of SoundcloudStreamExtractorTest should be updated to assert a minimum like count, like done in other services where it is applicable.