Add filtering to notification channel settings

Allow apps that are launching this page to specify targeted subsets of
settings that should be shown.

Test: settings notification robotests
Bug: 177246841
Change-Id: Ib491c43f1861a9775e3b25f39134cdbe105a7ff8

src/com/android/settings/notification/app/DescriptionPreferenceController.java

@@ -54,6 +54,11 @@ public class DescriptionPreferenceController extends NotificationPreferenceContr
         return false;
     }
 
+    @Override
+    boolean isIncludedInFilter() {
+        return false;
+    }
+
     public void updateState(Preference preference) {
         if (mAppRow != null) {
             if (mChannel != null) {