See the code comments for detailed explanation. But overall we use particular
combinations of sRGB and gamma 2.2 encode/decode to match SDR applications
while still ensuring HDR values are passed on linearly.
This means the user interface and SDR content will display different in
Windows HDR mode off and on, but that is consistent with other applications.
Split use_hdr variable into use_hdr_buffer about the graphics buffer,
and use_hdr_display about the chosen display in Blender.
Ref #145022
Pull Request: https://projects.blender.org/blender/blender/pulls/145025
5d72498154