Add the broadcast feature supported APIs

Expose isLeAudioBroadcastSourceSupported and isLeAudioBroadcastAssistantSupported APIs. It would just check the controller capabilities for now, and plan to check the profile enable status later.

Ignore-AOSP-First: Fix merge conflict
Bug: 150670922
Bug: 208368819
Test: make build
Change-Id: Ic68a19575e09dc8cf525c28afaca92ea44158981