Make systemui support waterfall

- Status bar content should be always below waterfall. We have to
minus status bar height with waterfall inset top to get the correct
content height and set the top padding/margin to waterfall inset top.

- Update paddings/margins for waterfall insets in below 3 places, which
also move setup rouned corner padding from ScreenDecorations to these 3
places.
   1. PhoneStatusBar
   2. QuickStatusBarHeader
   3. KeyguardStatusBarView

- Adjust notification minimum expand height for waterfall in
NotificationStackScrollLayout.

Bug: 146876976
Test: manual-select waterfall cutout overlay in develop option and check
the status bar.
Test: atest SystemUITests

Change-Id: Ib489e0ac69433635c3be990b5f8e56a3704b4a09