Restoring Network Available Notification to AGnssRil

Adds connectivity notification back for SUPL specific
case, needed esp. for case where WiFi is off and a
general purpose connectivity notification doesn't fire.

Bug: 33350903
Fixes: 33350903
Test: On device GPS-still-works checked, as well as notifications
      going into HAL on airplane mode on/off, and SUPL call flows
      (Further AGnssRil check to be done by partners)

Change-Id: I02af0b839d0bfd21dfefedff743208e02ab9c2dd