Fixed outgoing permitted logic

We allowed the 3p outgoing call when the foreground call provied by
CallAudioManager is null or can be held. However, the foreground call
can be the new outgoing call itself(the call state is CONNECTING) which
caused the failure of 3p outgoing call.

This also fixed the SelfManagedConnectionService cts.

Bug: 72028628
Test: Telephony sanity

Change-Id: Ia7696c7618e064ca10ae695a6bd597f3f012d717