Trying to use the display server as the QSV device was found to be
generally wrong in beta, so instead lets save defaults from the earlier
device enumeration similar to obs-ffmpeg-vaapi which is known to work
well.
VPL does not have a consistent initialization process for the various
backends it dispatches to. So this resolves the new VPL dispatcher
failing to initialize the video session when it dispatches to
intel-mediaSDK backend. On the oneVPL-intel-gpu backend VA-API sessions
are correctly initialized so this wasnt noticed when tested on newer
hardware.
