Don't set windowing mode in fullscreen displays.

We don't want to launch tasks in freeform mode in fullscreen displays
only because they were in freeform mode before.

Bug: 135941344
Bug: 135780225
Test: Manual tests.
Test: atest WmTests:TaskLaunchParamsModifierTests
Change-Id: Ifd466d1e11c8131ecf1e587aeac6f2eba15f6432