Enter QuiescentBluetoothRoute first when audio disconnect BT at the end

of the call.

Currently we try to enter QuiescentBluetoothRoute after request to audio
disconnect BT devices. This will cause the BT_AUDIO_DISCONNECTED coming
in when the state machine still in ActiveBluetoothRoute and we
mistakenly enter to earpiece route after the call even if the BT device
still connected to the phone.

Bug: b/306113816
Test: CallAudioRouteStateMachineTest
Change-Id: I57410e507e239b64470706c6ca59078c9eb84bdd