Modify desktop windowing initial bounds

Introduce dynamic bounds calculation for the desktop windowing intial
bounds which adjust to taskbar mode.

Fixes: 325028848
Fixes: 326224980
Test: atest WmTests:DesktopModeLaunchParamsModifierTests,
WMShellUnitTests:DesktopTasksControllerTest,
WMShellUnitTests:DesktopModeWindowDecorViewModelTests

Change-Id: Ic303853a05ae7e77c60dbc3941819434cfced075
6 files changed