API for accessing hit-test from Input Sources

[AdaRoseCannon]

The current seperation of concerns is Transient Input Sources vs Spaces.

The downside for this is that it creates a separation for handheld AR with transient input sources and head mounted AR.

The concerns for developers should be Hit Testing from Controller Inputs vs Hit Testing from Spaces. This would lead them down a path of supporting both by default.

This new API should treat both input sources the same which maybe in efficient but can be turned on or off depending on whether it is being used.

I.e. I am expecting input to place a 3D object so it is on. 3D object is placed so I am turning it off.