Set appBounds always in desktop mode launch

Now DesktopModeLaunchParamsModifier only calculates bounds if we know
tasks are definitely launching in desktop mode, so it is safe to always
set app bounds if caption insets should be excluded for unresizeable
apps.

Flag: com.android.window.flags.exclude_caption_from_app_bounds
Test: atest DesktopModeLaunchParamsModifierTests
Fix: 438437258
Change-Id: I3bb6b7633a6715c1d9721cfb413af37b4b5e8d9d