Fix potential Telecom crash if TelephonyManager throws exception.

TelephonyManager#isPotentialEmergencyNumber can throw an
IllegalStateException, and it can also rethrow remote exceptions.
Catching all is a safe means to prevent Telecom from crashing in either
case.

Fixes: 145790936
Test: Run unit test
Change-Id: Ib5556db72b02c3e113ded2bf6c61d0353e60a3b9