Dismiss education tooltips if the app handle/header is gone.

Fixes: 376172955
Fixes: 376174443
Fixes: 376398869
Fixes: 365056139
Flag: com.android.window.flags.enable_desktop_windowing_app_handle_education
Test: atest AppHandleEducationControllerTest and manual test
Change-Id: Ib26ced73c8a3cb96cccc68454aa30a89fea754f8