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/DeletedChannelsPreferenceController.java

@@ -51,6 +51,11 @@ public class DeletedChannelsPreferenceController extends NotificationPreferenceC
         return mBackend.getDeletedChannelCount(mAppRow.pkg, mAppRow.uid) > 0;
     }
 
+    @Override
+    boolean isIncludedInFilter() {
+        return false;
+    }
+
     public void updateState(Preference preference) {
         if (mAppRow != null) {
             int deletedChannelCount = mBackend.getDeletedChannelCount(mAppRow.pkg, mAppRow.uid);