Add relative APIs for InCallService that can support self-managed

connections that want to expose itself.

Add PhoneAccount#EXTRA_ADD_SELF_MANAGED_CALLS_TO_INCALLSERVICE and
Connection#onInCallServiceTrackingChanged.

Bug: 161144815
Test: CtsTelecomTestCases
Change-Id: I0a42ea79a1cd46aa9df3399c4fa2e9396321778a
Merged-In: I0a42ea79a1cd46aa9df3399c4fa2e9396321778a