Use BaseContainerInterface.getTaskDimension for windowSize in DesktopTaskView

- Instead of using widthPx/heightPx, use BaseContainerInterface.getTaskDimension that takes into account of whether Taskbar is persistent or pinned

Fix: 336788597
Test: Swipe up from Desktop; press recents button from Desktop
Flag: ACONFIG com.android.window.flags.enable_desktop_windowing_mode DEVELOPMENT
Change-Id: I04d3b5bbc577ea650f8a9dc45cc6d01bca3f6466