[Twitch] crash when stream goes offline

[mlburggr]

This is pretty difficult to replicate, but when you try to connect to a Twitch stream that just ended, the app crashes.

[hayksaakian]

the lines which parse individual qualities from the playlist throw the error in my local builds i just return early, as soon as we have a playlist url

if/when we support a quality-picker this might become a problem

[mlburggr]

this seems to be fixed