Fix invalid oauth window icon.
Fix invalid oauth window icon.

Regression of 2b65aa0

Klaudit/livestreamer-twitch-gui,Klaudit/livestreamer-twitch-gui,streamlink/streamlink-twitch-gui,chhe/livestreamer-twitch-gui,arclupin/livestreamer-twitch-gui,streamlink/streamlink-twitch-gui,chhe/livestreamer-twitch-gui,streamlink/streamlink-twitch-gui,Rekapper/livestreamer-twitch-gui,Klaudit/livestreamer-twitch-gui,bastimeyer/livestreamer-twitch-gui,Rekapper/livestreamer-twitch-gui,Rekapper/livestreamer-twitch-gui,bastimeyer/livestreamer-twitch-gui,arclupin/livestreamer-twitch-gui,bastimeyer/livestreamer-twitch-gui,arclupin/livestreamer-twitch-gui,chhe/livestreamer-twitch-gui