Support updated rendering of conversation icons.

Note that changes to channel settings now generate
onResume() for all available controllers to ensure they get
the updated drawable.

Bug: 149747760
Change-Id: I3f73c025b1d32194e3d5147d03cb781e370f2a1b
Test: make -j64 RunSettingsRoboTests ROBOTEST_FILTER="com.android.settings.notification"

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

@@ -74,8 +74,8 @@ public class ConversationImportantPreferenceController extends NotificationPrefe
         mChannel.setImportantConversation(value);
         if (value && bubbleImportantConversations()) {
             mChannel.setAllowBubbles(true);
-            mDependentFieldListener.onFieldValueChanged();
         }
+        mDependentFieldListener.onFieldValueChanged();
         saveChannel();
 
         return true;