There's now a new (yet another, sigh) section in Settings -> General, which lets you set streamer mode to 'enable/disable/detect obs' and there are also separate settings for each of the things that streamer mode covers. I just have to add ping sounds and PR is ready to be merged :)
* Show "Streamer Mode" image as link thumbnails if applicable
* Moved hideViewerCountAndDuration to streamerMode settings
Set it to false by default (just how it used to be under /misc settings, also reworked live tooltip to be a bit prettier and say "<Streamer Mode>" in gray instead of "Live with <hidden> for <hidden> viewers"
pajlada