Listen to changes in the original connection for domain tracking

In EmergencyStateTracker, we need to know the domain of the call
in order to perform different procedures when we move into ECBM.

This change adds a listener that fires when the original
connection changes, causing us to be able to determine which
domain the emergency call is going over.

Bug: 247639718
Test: atest TeleServiceTests:TelephonyConnectionServiceTest; Placed call/sms, used data
Change-Id: I38ebd47a70687395d868b507549b98b0c6b36045
1 file changed