Update picture-in-picture settings to match mocks.

- Removing switches in top-level picture-in-picture settings, adding
  details screen for each app which contains the switch and some
  additional information.

Bug: 35957404
Test: make -j40 RunSettingsRoboTests
Change-Id: Ib22df8a52ab857e071ec43dd3e5d1f5282db35cb
diff --git a/src/com/android/settings/Settings.java b/src/com/android/settings/Settings.java
index f2d6452..8f645f8 100644
--- a/src/com/android/settings/Settings.java
+++ b/src/com/android/settings/Settings.java
@@ -95,6 +95,7 @@
     public static class NotificationAccessSettingsActivity extends SettingsActivity { /* empty */ }
     public static class VrListenersSettingsActivity extends SettingsActivity { /* empty */ }
     public static class PictureInPictureSettingsActivity extends SettingsActivity { /* empty */ }
+    public static class AppPictureInPictureSettingsActivity extends SettingsActivity { /* empty */ }
     public static class ZenAccessSettingsActivity extends SettingsActivity { /* empty */ }
     public static class ConditionProviderSettingsActivity extends SettingsActivity { /* empty */ }
     public static class UsbSettingsActivity extends SettingsActivity { /* empty */ }