Allow shell uid to access Vr APIs

Some of the Vr APIs in VrManagerService need to be accessed via shell to
be used for testing and for easy access. Add
android.permission.RESTRICTED_VR_ACCESS to shell uid.

Bug: 36071574
Test: adb shell vr set-persistent-vr-mode-enabled true
      adb shell dumpsys vrmanager
      >> Persistent VR mode is currently: enabled
      adb shell vr set-persistent-vr-mode-enabled false
      adb shell dumpsys vrmanager
      >> Persistent VR mode is currently: disabled

Change-Id: I486fa19f93d5c6999aa479fdf7e5f2f48f765240
Signed-off-by: Karthik Ravi Shankar <karthikrs@google.com>