LeAudio: Minor logging and comments improvement

Bug: 308428860
Bug: 332476151
Flag: EXEMPT; no functional change - logging function verified by the unit test
Test: atest --host bluetooth_le_audio_codec_manager_test --no-bazel-mode -v ; Verify the output for the log messages.
Change-Id: I628564a4fb82f8a065ab5da868eef1b71b81c005