[2/n] Exclude caption from initial bounds in core

Desktop tasks launched from taskbar are sent with pending intent and
freeform windowing mode set from shell to core. Currently, exclusion of
caption insets from app bounds are only set in WindowDecoration#relayout
which is too late in the activity lifecycle as configuration has already
been resolved.

Exclude caption insets in task app bounds in launch params calculations
to ensure correct calculations.

Flag: com.android.window.flags.exclude_caption_from_app_bounds
Test: atest DesktopModeLaunchParamsModifierTests
      atest LaunchParamsControllerTests
Bug: 399544381
Change-Id: I411eeacd8d9b37b725f41ca428e20196c8e90904