App default has aspect ratio override

Allow user to set the app default aspect ratio. App default was behaving
the same as fullscreen.

Test: manual, default aspect ratio is different from fullscreen as
before universal resizable by default
Test: SizeCompatTests
Flag: com.android.window.flags.universal_resizable_by_default
Bug: 378880473

Change-Id: I78464df5ee2ff4e06beb1a4b3c7ec54d19603dad