Add AppSettingsPreference for Spa

This is used in new App Info page.

To try:
1. adb shell am start -n com.android.settings/.spa.SpaActivity
2. Go to Apps -> All apps -> [One App] -> Additional settings in the app

Bug: 236346018
Test: Unit test & Manual with App Info page
Change-Id: I40a175d771c4c0f13986f8c615169c99ce1b0623