Fix deathRecipient of BluetoothAudioProvider

The "provider" is managed with a shared_ptr but we do not hold it and
instead are giving the raw inner pointer as binderDiedCallbackAidl.
This can randomly generate crash as the provider may be freed outside of
this code.

Replacing the provider with a context that we can manually allocate and
deallocate.
Setup AIBinder_DeathRecipient_setOnUnlinked to clean the data allocated

Bug: 245009140
Test: m android.hardware.bluetooth.audio-impl and start / stop session +
      manually kill bluetooth process during audio play
Change-Id: I0c14c062a8bde7e532ff02f01991d66da33ec569