Correctly use areDesktopTasksVisibleAndNotInOverview() in DesktopVisibilityController

- The refactoring ag/30993068 mis-use areDesktopTasksVisible() instead of areDesktopTasksVisibleAndNotInOverview()
- This causes Taskbar mode to change at wrong timing

Bug: 388266322
Test: Swipe up from fullscreen app, launch desktop task
Flag: EXEMPT bugfix
Change-Id: I75a4c7497fe7e4d03a4029d678086f859c8c55b8