Make sure tasks are launched on the right display in desktop mode.

The task was launched on the default display, but with transitions that
expected a specified display, leading to weird result (e.g. full screen
on external display). Setting the display seems to solve
that issue.

Bug: 403506870
Flag: com.android.window.flags.enable_start_launch_transition_from_taskbar_bugfix
Test: atest DesktopTasksControllerTest
Test: Build and run
Change-Id: I1648d1bc1cc56db0e381cc31f6954cbec34cff23