Handle low battery ImsReason and translate to low battery disconnect cause.

There are two scenarios where we can run into a low battery:
1. onCallTerminated - this would be a mid-call termination.
2. onCallStartFailed - this would be while dialing.

Modified getDisconnectCauseFromReasonInfo to generate the correct
disconnect cause based on whether the call being disconnected is in
progress or dialing.

Test: Manual
Change-Id: If8672f4fb34e63f68868821b1fb203cd2676f78b
Fixes: 63936576