DO NOT MERGE - Fix StatusBar.updateIsKeyguard() when suspending to RAM.

That method was throwing a NPE on automotive because it's called before start()

Test: check logcat while running 'adb shell dumpsys car_service suspend'
Fixes: 146144370
Change-Id: Id863acac44f75b06c8cd1a0f0bcd6f23f8ab6fd9
(cherry picked from commit 20e362a92b8376b590d5df615265050dd6838c91)