broadcast: Don't stop ISO when there is active Unicast

Broadcast and Unicast uses ISO module for handling controller actions.
Cleaning up module have to check if other module Broadcast or Unicast is
active to not block access to controller.

Tag: #bug
Bug: 328533583
Bug: 316005152
Test: atest bluetooth_le_audio_client_test
Change-Id: Id11c68e28ced9678720bfd9fa7b50829e64dfa28