Adding XR permissions

The intended state of XR permissions is documented at go/openxr-permission-validation, with follow-up privacy changes in go/xr-tracking-permissions and go/android-xr-permission-concerns. These have all undergone privacy review.

Bug: 364416355
Change-Id: I526bdeb6d01019ec0634e051d471146cb4b2aafa
Flag: android.xr.xr_manifest_entries
Test: Checked that the project still compiles. No code changes.