Channel updates from users lock fields from interference.

Also some apis have changed.

Test: manual, modify settings and check policy xml.

Change-Id: I967cb1fb30d8d400bdc0f3aa92fa07b4c87ddcf5

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

@@ -102,7 +102,7 @@ public class AppNotificationSettings extends NotificationSettingsBase {
             mChannelList = mBackend.getChannels(mPkg, mUid).getList();
 
             setupImportancePrefs(mAppRow.systemApp, mAppRow.appImportance, mAppRow.banned,
-                    NotificationManager.IMPORTANCE_MAX);
+                    NotificationManager.IMPORTANCE_HIGH);
             setupPriorityPref(mAppRow.appBypassDnd);
             setupVisOverridePref(mAppRow.appVisOverride);