Revert "Messaging: Add "Mark as read" quick action for message notifications"

This reverts commit f19e916a0d.

Reason for revert: Reverting per Taesu Lee's comments, because it doesn't work and has issues.

Change-Id: I778362b628f4c3ae076dd943e77dee415984fba0

src/com/android/messaging/datamodel/MessageNotificationState.java

@@ -349,14 +349,6 @@ public abstract class MessageNotificationState extends NotificationState {
                     getClearIntentRequestCode());
     }
 
-    @Override
-    public PendingIntent getReadIntent() {
-        return UIIntents.get().getPendingIntentForMarkingAsRead(
-                    Factory.get().getApplicationContext(),
-                    mConversationIds,
-                    getReadIntentRequestCode());
-    }
-
     /**
      * Notification for multiple messages in at least 2 different conversations.
      */