Hide status bar icons if showing bouncer on keyguard activity

When in a keyguard activity, we want to hide the status bar icons when
the status bar window is hidden or the bounce is showing.

Test: launch camera from keyguard, press home to show bouncer, don't see
icons
Fixes: 80107240

Change-Id: I66dd923da2b63b20fd766f8223de90f19e86b36e