libobs-d3d11: Default to Intel IGPU on IGPU+DGPU systems

On systems that have both Intel iGPU and Intel dGPU at the same time,
default/prioritize running OBS the iGPU instead to improve performance.
The user can still choose the dGPU if they change the adapter index, but
the adapter index will now be the second value instead of the first
value. (-Jim)