Launcher: Make `RecentTasksController.getRecentTasks()` multi-desks aware

This is the Launcher-side CL  of the companion CL ag/31825217.
This CL changes `GroupedTaskInfo` and `RecentTasksController.getRecentTasks()`
such that multiple desktops are supported.

Bug: 395911284
Test: m
Flag: com.android.window.flags.enable_multiple_desktops_frontend
Flag: com.android.window.flags.enable_multiple_desktops_backend
Change-Id: I856768d03460054ccd7056f87e16dcb65ced47fb