Deactivate notification listeners disabled at runtime.

PACKAGE_CHANGED is called when either the application or any
of its components change.  Rework old early exit code to
handle component-level disabling wrt listeners.

Note PACKAGE_CHANGED can take quite a while to reach NMS.
Up to ten seconds (!) after component-disabling in app.

Bug:8982243
Change-Id: Ia325516140dd9288466a663192a5326019f071ab