Ensure connection extras set before connection start are passed through.

In ImsPhoneConnection, the extras pertaining to a "Child number" were
set on the ImsCallProfile prior to the connection being created.  Turns
out we only pass along extras when they're changed.  However, when the
connection is new we never call the callback to indicate the connection
extras changed.

Added code in ImsPhoneConnection to set the extras when the connection
is first created.

This ensures the extras make it to InCall for incoming calls.

Bug: 24585039
Change-Id: I90993a278b76371bf514fd332adf78bc58505357