Turn off RTT if a carrier doesn't support it

If a SIM of a carrier that doesn't support RTT is inserted, turn off RTT
in ImsConfig.

Fixes: 154166852
Fixes: 160208736
Test: manual
Change-Id: I680fc9dd64c9f631ce0bfb8d0fafee41924cefb2
(cherry picked from commit eff7d7859c9204948bec01b49d60d07538ca312a)