Don't update flexible option bounds if fullscreen override applied

Currently if option bounds are marked as flexible, the desired size of
an application is recalculated and the option bounds size is updated.
However, if the fullscreen override is applied, there is no need to
recalculate the desired size or the cascaded position so we can simply
just inherit the existing option bounds:

Flag: com.android.window.flags.enable_shell_initial_bounds_regression_bug_fix
Fixes: 400851216
Test: atest WmTests:DesktopModeLaunchParamsModifierTests
Change-Id: I03d83d14f8727050b9dfa10773498ddc7211838e