Fix data limit notification issue

The data limited sim card has been plug out,
but it’s data limit notification didn’t dismiss.
It should cancel notification in function updateNotificationsNL(),
but it returned. And the mActiveNotifs has clear.
So it never has change to remove the notification later.

Bug: 161101175
Test: com.android.server.net.NetworkPolicyManagerServiceTest All pass
Change-Id: Ia08f443a88e2c9150fa2e6f474688e091d3a437b