Fixing conference merge where only one party is added to conference.

- Adding check in TelephonyConnection to check for changes to the
multiparty bit and notifying listeners (in this case the conference
controller.
- In ImsConferenceController Responding to the onConferenceStarted
callback from the IMS layer by checking if a new ImsConference needs to
be created.

Bug: 18960042
Change-Id: I8dd2f32c442895fd6126b83f2d8ac889fd468fad
2 files changed