Update visual indicator on tiling to match tiled size.

Tiled apps can be tiled smaller or larger than half the screen depending
on the app tiled previously and its size.

This CL updates the tiling visual indicator to match the size of the tiled
app.

Flag: com.android.window.flags.enable_tile_resizing

Test: unit tests and on device testing

Bug: 379664855
Change-Id: Ia3786a644d183e588ce4cbaffb8e43dac41019c6