Fix CTS test on devices not supporting concurrent display

In onSupportedStatesChanged and
updateRearDisplayPresentationStatusListeners, it tries to get the rear
display metrics, which will crash on devices without the mode.

Bug: 251747141
Test: atest ExtensionWindowLayoutComponentTest
Change-Id: I8698e62fdb414f798b9268d568119e9be2712f72
1 file changed