[bc25] Add Dual Shade invocation zone detection.

When detecting swipe gestures in dual shade, the top edge is split in
two: left and right. On narrow screens (aka handheld form factor), this
split is right down the middle of the screen. On large screens however,
the split happens in the status bar area between the notification icons
and quick settings icons.

Since the status bar doesn't yet report to SceneContainer the coordinate
of the split in the latter case, in this CL we use an interim value of
80% of the screen width to get an approximate effect.

As an example of how split-edge actions are defined, they were added to
the actions view-model for the shade overlays. User actions in the rest
of dual shade entry points will be updated in a follow-up CL.

Bug: 338577208
Bug: 338033836
Bug: 356596436
Flag: com.android.systemui.scene_container
Flag: com.android.systemui.dual_shade
Test: Added unit tests.
Test: Existing unit tests still pass.
Change-Id: Ic209a812ef2321808d6f15467cf02ee39a85e879