leaudio: Notify new configuration only when streaming starts

Without this patch CodecConfigurationChanged will be sent to java also when
UpdateMatadata is finished or when late connect happens.
LeAudioService then notifies Audio Framework which triggers Audio Framework to
read configuration. This operation cause reduntat audio pause.
This issue happens only when flag
leaudio_codec_config_callback_order_fix is set.

Bug: 336453376
Bug: 326442537
Test: atest bluetooth_leaudio_client_test
Change-Id: I465ba452e74a5811c62904a94a4441da37fb6919