le_audio: Wait for all CISes and Data Paths to be complete

Wait with StatusReportCb streaming until Data Path is set up.
It's crucial to report the status when everything is set up
properly, because once client.cc StatusReportCb handler is called,
the audio configuration is updated and applied to codec.

Bug: 393097399
Flag: Exempt; regression covered with unit test added
Test: atest bluetooth_le_audio_test
Change-Id: I890041b40cb50f44b80b9d2d357e16e8b5c4e762