Add cross stack redialing during emergency call

If an emergency call is initiated during a non-emergency NTN session,
the subscription currently in progress with the emergency call becomes
inactive and the subscription in other stack becomes active. Due to this
situation, an emergency call is connected through other stack about 3
minutes later.
This change is to ensure that when the above situation occurs, the
emergency call can be connected quickly by determining whether an
emergency call is possible to other stack at an early stage of the
domain selection procedure.

Bug: 389190613
Flag: com.android.internal.telephony.flags.perform_cross_stack_redial_check_for_emergency_call
Test: atest EmergencyStateTrackerTest
Test: manual (verified quick cross stack redialing during emergency call
while non-emergency NTN session is in progress)
Test: manual (verified emergency call using test emergency number)

Change-Id: I86f59b4718e93f041b22621e45e22b60152b7636