Exit desktop-immersive when app unrequests immersive

Resizes the app back to maximized bounds when it stops requesting
immersive mode.

Flag: com.android.window.flags.enable_fully_immersive_in_desktop
Bug: 369443574
Test: enter desktop immersive with YT Music, exit using app UI, verify
app resizes back into maximized size

Change-Id: I937ffe7b61b0246358d3c63a978ca0eb64ae6b43