Broadcaster: Improve broadcast stream metadata

This adds the missing CCID list for the metadata update procedure,
adds proper support for multiple bits in the context map and updates
metadata on track metadata change.

Bug: 240145685
Tag: #feature
Test: atest --host bluetooth_test_broadcaster --no-bazel-mode
Change-Id: Ia14947d3e41c93cd21fc579c60e938b17c6861bc