Adjust the RAT preference when SIM is absent

There can be countries where emergency calls on 2G networks
are more stable than other networks when SIM is absent.

Per configuration, adjust the RAT preference for network scan
when SIM is absent.

Bug: 335537430
Test: atest EmergencyCallDomainSelectorTest

Change-Id: I4751bffb4903d680355dc2dddd870dc649c2c502
3 files changed