Add isAospDomainSelectionService to TelephonyManager

EmergencyCallDomainSelectionTestOnMockModem is a test
for AOSP domain selection service.

It determines whether the AOSP domain selection
service is running or not with this API.

Bug: 333893700
Test: atest EmergencyCallDomainSelectionTestOnMockModem
Change-Id: Ia5ee0074b3ebd95fe883ceb7eb4c3ab5eef4b008