Change fallback closing animators for Desktop Mode.

The main changes are:
1. the amount to move the window horizontally (much less for Desktop
Mode), and
2. the timing for when the alpha animation is applied - we remove the
   25ms delay for freeform windows.

Bug: 378675987
Test: manual
Flag: com.android.window.flags.enable_desktop_windowing_exit_transitions
Change-Id: Ieeb6b827eee2e6314ea9c79213cdf401f48d3c85