Don't only change windowing mode of root task when requesting task for windowing mode

If a task doesn't have a root task and a windowing mode is requested, it should still be honored.
Call on the non-roottask version of setWindowingMode.

Bug: 416588577
Test: Manual. Intent launches with launchWindowingMode is now respected
Flag: EXEMPT bugfix
Change-Id: Id915c02ff3345d267a075897c67afbf56ff2a6e3