Send SMS over 1x when on eHRPD and active voice call

When UE is attached to eHRPD network and IMS is registered:
- If there is an active 1x RTT voice call, send SMS over 1x
- If there no active 1xRTT voice call, send SMS over IMS

This feature is enabled by default. To disable it, set
config_send_sms1x_on_voice_call to false in config.xml

Change-Id: I767ff1747c8498a5fd3760e2a8a6cbd764716b37
CRs-Fixed: 565247