Renaming XR.HandsState.GetHandTransform()

[nkast]

The OVR (pc/meta link) is outdated. How should we shape the XR api?

[nkast]

See also #2257

[squarebananas]

I was thinking TargetAim, because if someone from an OpenXR background types Aim or someone from a WebXR background types TargetRay, both will see intellisense provide the new name as it's a combination of both.

No strong preference though, as long as it isn't just Hand.