Use shorter playlists for youtube tests

[ivanistheone]

The playlists used in the tests
https://www.youtube.com/playlist?list=PLBO8M-O_dTPE51ymDUgilf8DclGAEg9_A
and https://www.youtube.com/playlist?list=PL7m903CwFUgntbjkVMwts89fZq0INCtVS
are quite large so downloading testing videos takes a long time (e.g. the video oP4I9LKANew is 256.88MB).

We should replace with test playlists created by LE with small and fewer videos (since main purpose is to check license).

Same goes for the individual test videos with subs (the test just broke today because new subs were added, so I'll have to replace those test youtube videos with ones uplaoded by us that we know won't change).