Improve cutout related performance

The cutout is now provided as a derived state from insets so it doesn't trigger recompositions every time insets change (but only when the actual cutout changes).
Also it is now read later in several cases, only when needed.

Bug: 417960167
Flag: com.android.systemui.shade_window_goes_around
Flag: com.android.systemui.scene_container
Test: Verify the shade header flicker when moving the window between displays is not there anymore
Change-Id: I0c5157c035901127c1339c49bc3131fc1f2d4ab1