AOD notification icons placement

Whenever there's a custom clock, notification icons should be on the top
left. The default clock will just show the dark shelf.

Test: atest NotificationStackScrollLayoutTest
Test: atest CollapsedStatusBarFragmentTest
Test: visual - with and w/o clock plugin
Test: visual - with and w/o RTL layout
Bug: 122301289
Bug: 111405682
Fixes: 120563185
Change-Id: I4c513d347f656262ee6f91bd208ab9f219e4419c