HFP: Indicate profile as connected after SLC is established

* HFP profile connection require RFCOMM connection first and then a
  Service Level Connection (SLC) on top of RFCOMM
* HFP profile is only considered fully connected when SLC is
  established
* Bluetooth stack currently sends
   BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED when RFCOMM is
  connected. Instead, it should send it when SLC is established.
* This CL fixes the above issue by sending connection state changed
  intent after SLC is established.
* This CL also removes instances where emitted connection state changed
  intents have same new state and previous state (i.e. no real state
  change)
* Moved processSlcConnected out from headset state machine to
  queryPhoneState()

Bug: 63775402
Test: HFP and HSP PTS tests, HFP regression
Change-Id: I0d4e1c17f502968e4f88f3c11c2b8001dc79f7b9
Merged-In: I0d4e1c17f502968e4f88f3c11c2b8001dc79f7b9
(cherry picked from commit 39af3989)