Do not process call intent if call already disconnected

In cases of very quick call and hangup (delay of 0.1 sec using
automation) the call itself will go from NEW -> CONNECTING ->
DISCONNECTED but the CallIntentProcessor will still make the outgoing
call since it does not check the current call state for it has been
disconnected.

Bug: b/28969591
Change-Id: I1de45ff342db3e2552824c17f9f73f9c3a2579d9