Add multisim notifications for SST

ServiceStateTracker posts notifications for restricted state and
rejection cause for CS registrations which need to be customzied for
multisim cases.

Bug: 69928579
Test: ServiceStateTrackerTest
Change-Id: Ia7db81da6dd858b99113432a97fb489dbebe2436
Merged-In: Ia7db81da6dd858b99113432a97fb489dbebe2436