Let WM shell set launch display area per params

There are needs in foldables and new split screen to route new tasks
with certain activity type and windowing mode to specific display areas.
This CL fulfills this need.

Bug: 175140202
Test: atest TaskLaunchParamsModifierTests
Change-Id: Id42371ce0ccbfb00776dd9364d95292cdff56f4f
3 files changed