AudioService: reapply remove BT device connection message

Remove unnecessary AudioService message when processing
handleBluetoothActiveDeviceChanged() API and post
AudioDeviceBroker messages directly instead.

Do not acquire mDeviceStateLock mutex when posting messages in
AudioDeviceBroker.queueOnBluetoothActiveDeviceChanged

Bug: 385262729
Test: Manual Bluetooth audio regression
Test: atest AudioDeviceBrokerTest
Test: atest AudioDeviceInventoryTest
Flag: EXEMPT bug fix
Change-Id: I9d8a01e1428559a797c7d21955441a51f12150df