leaudio: Make sure context and locations are updated correctly

With this patch available group contexts and locations are updated in following
points of time
1) When device got disconnected
2) When notification arrives but group is not streaming
3) when streaming ends
4) when device got connected

Also note, that whenever leaudio code get latest available context type
it just look into connected devices

Bug: 281957456
Tag: #feature
Test: atest bluetooth_le_audio_client_test

Change-Id: I7a86c6520a708291f2f05c1750c005732bc379d6