plugins/screencast, screenshot: switch color transforms to relative colorimetric
This is to disable tone mapping, which makes screenshots of SDR things while HDR is enabled on a display look a lot worse. As the tradeoff, this will make HDR content look worse, but that can be fixed later by taking the actual HDR metadata into account.
(cherry picked from commit d62eb367)
Co-authored-by: Xaver Hugl xaver.hugl@gmail.com