[peertube] Extract files also from streamingPlaylists (#27728)
[peertube] Extract files also from streamingPlaylists (#27728)

JSON objects with an empty "files" tag seem to be a valid PeerTube API
response. In those cases the "files" arrays contained in the
"streamingPlaylists" members can be used instead.
closes #26002
closes #27586
rg3/youtube-dl,Tatsh/youtube-dl,rg3/youtube-dl,ozburo/youtube-dl,Tatsh/youtube-dl,ozburo/youtube-dl