IMS: Do not update connection state for onCallUpdated callback.

onCallUpdated callback is to inform updates on parameters of ImsCall
other than the call state. Updating the call state during onCallUpdated
is sometimes corrupting the connection state, especially during
hold/resume operation. Hence refactored code to not update state
of connection for call updated callback.

Change-Id: I55ed948fe3b5b03f8836b84d7952a39f97cd2a8a
Bug: 22170586