Change onRemoteEntry() to only fire when entries are removed

Conceptually, this should be a paired match with
onNotificationAdded(). Previously we were firing this method even
if the notification was no longer present (already removed) or
if it hadn't been added yet (was in pending).

Test: atest

Change-Id: I613f60aa8cf4e1aeb7bb13ff5883a221c9b623c6