Add EmergencyStateTracker for domain selection.

Requirement 1 - Track Emergency Call State and Notify Radio/Listeners:
- Turning on the radio and switching DDS is moved to EmergencyStateTracker.
- The existing logic for tracking the emergency call state of the device is moved from Phone.java.
- Sending the emergency mode to the modem on a per-transport basis and notifying changes to emergency mode to the modem.
- Notifying changes to the emergency mode to external app listeners.

Bug: 247639718

Change-Id: I8ada9fe29ad999484206d94ca7ce8579dcf9d542