Migrate status bar to the flexible insets API

This CL removes the hard-coded logic in the frameworks and use the new
flexible insets way to implement the status bar related insets. This
moved the display cutout touchable region related calculation from the
DisplayPolicy in the system core to the StatusBarWindowController.

Test: DisplayPolicyInsetsTests
Bug: 239145252
Change-Id: I9911597e6522625e22857821f4c8f0b1dc5b17f4