Notification settings updates

- Text changes
- Show channels on the app settings screen (again)
- Hide most of the channel settings under 'advanced' (note: this hides
  the footer preference(s) also, at the moment. the functionality
  to exclude those is coming in a later cl)
  - Add a 'show notifications' toggle for each app created group

Bug: 63927402
Test: make RunSettingsRoboTests

Change-Id: I9906ef943d05e1915061b59294a25d81c4e6cbb5

src/com/android/settings/notification/BlockPreferenceController.java

@@ -67,6 +67,8 @@ public class BlockPreferenceController extends NotificationPreferenceController
         LayoutPreference pref = (LayoutPreference) preference;
         SwitchBar bar = pref.findViewById(R.id.switch_bar);
         if (bar != null) {
+            bar.setSwitchBarText(R.string.notification_switch_label,
+                    R.string.notification_switch_label);
             bar.show();
             try {
                 bar.addOnSwitchChangeListener(this);