Add check for the device having "feature face" before requesting the service

Personally, I think it'd be better for the service to return null rather
than throwing an error if it doesn't exisit but according to b/135475155
throwing is WAI.

Test: try running any test that might use ExandableNotificationRow on a
      device without face service and see that an exception isn't thrown
Bug: 135475155
Merged-In: I6cf7f3d39f411dc88d5fd75da0adb2c612acf880
Change-Id: I6cf7f3d39f411dc88d5fd75da0adb2c612acf880