Provide reason for moving task to front.

In WM Shell we want to be able to log the reason a task was unminimized,
with this CL we pass a reason from Launcher to WM Shell when bringing
the task to front.

Test: manual
Bug: 357985747
Flag: com.android.window.flags.enable_desktop_windowing_mode
Change-Id: I4a68f4d0d7eddb483a1473843b4cd91bd783d92f