Bluetooth audio hal check broadcast configuraiton for the broadcast offload

The patch contains the following changes
1. Check the broadcast audio configuration as starting broadcast offload
   session
2. Update audio configuration checker for broadcast offload
3. Remove the IsOffloadLeAudioConfigurationValid function that the audio
   configuraiton is invalid as session started, so we don't need to
   check it at that time

Bug: 210987580
Test: start the offload broadcast stream, and check the session status
Change-Id: I60b1b506051873f6d942f2febace6562634fc12a
Merged-In: I60b1b506051873f6d942f2febace6562634fc12a
(cherry picked from commit ee398a93)