[XR] Update depth sensing implementation to support the new specs

[RaananW]

These specs - immersive-web/depth-sensing#42 are already implemented in the oculus browser.
This allows using depth sensing for occlusion.
We need to make sure we don't break current devices using it while supporting the new features.

[github-actions]

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[matthargett]

Would be great if this was reconciled on visionOS devices as well. While Vive XRE has a depth sensor, sadly their browser barely supports base WebXR 1.0 and doesn't remotely leverage the strength of their hardware (as of June 2024, anyway).

[RaananW]

Would be great if this was reconciled on visionOS devices as well. While Vive XRE has a depth sensor, sadly their browser barely supports base WebXR 1.0 and doesn't remotely leverage the strength of their hardware (as of June 2024, anyway).

This very much depends on vendor implementation. If Apple decides to expose this feature, we will be able to use it. So far, AFAIK, the only browser that supports the new specs is the oculus browser.