Non-blockable whitelist should only control importance fields

Sounds, etc. should still be modifiable

Test: robotests
Fixes: 130086523
Change-Id: I1a95a73b299bb3afd169b249a3dabae3583a448a

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

@@ -110,7 +110,7 @@ public abstract class NotificationPreferenceController extends AbstractPreferenc
         }
     }
 
-    protected boolean isChannelConfigurable() {
+    private boolean isChannelConfigurable() {
         if (mAppRow != null && mAppRow.lockedImportance) {
             return false;
         }