leaudio: Improve stream reconfiguration

If during stream releasing (e.g. for reconfiguration), the Audio HAL
calls onAudioResume, BT stack will return pending instead of cancel
and let Audio HAL to wait for the release to be completed (or
reconfiguration completed).
After that BT stack will Cancel previous request and wait for
another resume to start stream if still needed.

Bug: 150670922
Test: atest --host bluetooth_le_audio_test bluetooth_le_audio_client_test
Sponsor: @jpawlowski

Change-Id: Ib467a29c70370a6e17c5774b1b6da57f496b95ab