leaudio: Improve inactivating LeAudio device

with this patch, we notify Audio framework as soon as possible that
LeAudio group is going to be inactive, without waiting for Native to
acknolege group inactivation.

Bug: 242908683
Test: atest BluetoothInstrumentationTests
Tag: #feature
Change-Id: I426f2a933ddc265e1d55fc89eff4f19bed71a119