stream.hls: Fix UnicodeDecodeError for log msg and name_prefix for stream_name
stream.hls: Fix UnicodeDecodeError for log msg and name_prefix for stream_name

wlerin/streamlink,beardypig/streamlink,chhe/streamlink,streamlink/streamlink,bastimeyer/streamlink,gravyboat/streamlink,chhe/streamlink,bastimeyer/streamlink,gravyboat/streamlink,melmorabity/streamlink,streamlink/streamlink,beardypig/streamlink,melmorabity/streamlink,wlerin/streamlink