Fix emergencyDial tests in VTS 1.6

 cherry-pick from aosp/1708089

 - Change to calling getVoiceRegistrationState_1_6() instead of getVoiceRegistrationState().
 - Fix incorrect voice registration state value


Bug: 187488263
Test: atest VtsHalRadioV1_6TargetTest

Merged-In: Iebf32061c7944104a8d4a0297af9204ca214e627
Merged-In: Ic2745c48b3d3451e5065a77054d9e7b930ea4ce5
Merged-In: I787ead62a70acd69a4676d5e53509fe2ff6b0fd8
Change-Id: I0a04238f03c7d4fe1eae00c33c18d6dd9da610a8