Check the ignore rtt setting carrier config

When making calls, check the ignore RTT setting carrier config in
addition to the RTT setting. If we're supposed to ignore the RTT
setting, keep all calls as voice calls unless they've got that extra
attached to them that says that the call is supposed to be RTT.

Bug: 136035164
Test: manual
Change-Id: I9b9ce8f90cd50014bffa18ea9b8fc003c6acc9f8