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: I3d9937d24fa38b8d044b88d1146bd6a96dd97f30
CRs-Fixed: 768450