Add support for network identified emergency calls.

Add support for the IMS call profile to indicate that a call is an
emergency call.
Add supporting connection and call properties so that this can be
propagated to Telecom and ultimately the Dialer app.
Add System API to determine if the device is in a network IDed or dialed
emergency call (used in Telephony).

Test: Manual test using test intents and ecclist property.
Test: Added new telecom unit tests.
Bug: 77565333
Change-Id: I769e7b5000b10662c08fe53c91ef99edc685d2b1