Add "Don't suggest app" shortcut to suggested apps.

This works for suggested apps in both Home and AA+. When enable_shortcut_dont_suggest_app is true, the secondary drop target "Don't Suggest app" is removed instead "Don't suggest app" is added to shortcuts.

Video: https://b.corp.google.com/issues/319250810#comment5

Home: https://screenshot.googleplex.com/d7Wts48X6EmFAYg.png
Private space app suggested: https://screenshot.googleplex.com/BukzCRTvkzbpwQ3.png

AA+: https://screenshot.googleplex.com/ADMCHnQ378jvJEE.png
Private space app suggested : https://screenshot.googleplex.com/AYga8Km3646AqMt.png

Bug: 319250810
Flag: aconfig com.android.launcher.enable_shortcut_dont_suggest_app DEVELOPMENT
Test: Manual.

Change-Id: Ia7df749a1c7d806bd9d74124be138384c3050119