Store the reference to Phone to handle asynchronous response with the Phone

TelephonyConnection losts the reference to Phone while reselecting
domain by removing the stale original connection.

Bug: 266191349
Test: atest EmergencyCallDomainSelectionTestOnMockModem#testDefaultCsThenPs
Change-Id: Id755e6622345e2b3bbf5903b35eba31575d6f0bd
1 file changed