Do not move home when starting recent task from non-recents

The move-home case is only needed when using 3rd-party launcher.
I.e. RecentsActivity will be used. Such as quick switch to app on home.
The stack will be home->recents->app. Then after going back from app,
it should be home instead of recents.

Since the WindowContainerTransaction#startTask also uses
startActivityFromRecents, the caller can be systemui (not recents).
And it only wants to move the task to front without moving home.

Bug: 345186561
Flag: EXEMPT bugfix
Test: Assume Task1 and Task2 belong to a test app.
      Launch Task1. Return to home. Launch Task2.
      Task2 starts Task1 by startActivityFromRecents.
      Press back key. The next should be Task2 instead of home.
Change-Id: I6219614ae46291db8b6cdd3be795a1262931b6b1