Use enhanced barriers on dx12 (where possible)

[Vecvec]

Is your feature request related to a problem? Please describe.
Currently we are using what directx12 calls "legacy barriers" which can be expensive and when support for DXR comes in (#6777), place_acceleration_structure_barrier will cause GPU execution stalls.

Describe the solution you'd like
Using enhanced barriers where possible would allow for more optimal barriers in certain places (especially in place_acceleration_structure_barrier)

Describe alternatives you've considered
Don't support this - it's optional.

Additional context
This feature is optional and so we would still need the old code paths anyways.