Load headless system app cache on boot.

AppStandbyController.initializeDefaultsForSystemApps() is only called
when there's a system update. The headless system app cache needs to be
loaded on every boot, so this moves the loading to the on-boot path.

Bug: 155761007
Test: reboot device multiple times
Change-Id: I94fd6a85b791388f937e208448c6b38d9639005e
1 file changed