leaudio: Fix clearing state machine

This patch fixes scenario when during stream releasing one device got
disconnected while the first one was properly moved to IDLE.

In such a case, client.cc would not be notified about IDLE state which
would result in stream not being able to restart after all.

This patch also fixes typo in IsCisPartOfCurrentStream

Bug: 286402912
Test: atest BluetoothInstrumentationTests
Test: atest bluetooth_le_audio_test
Tag: #feature
Change-Id: I17133983af51ad9e13458b4e6fec6e47a5c176f5