leaudio: Fix stopStream while late attach.

This patch adds test case which is verifing that group is properly stopped
when it is initiated while attaching device is changing ASE state trying to get to stream.

Bug: 331775328
Flag: Exempt, regression tested with unit test, new test added
Test: atest bluetooth_le_audio_test

Change-Id: I278161e8a48fad0d2cf171578a8753d7a456cc11