Merge "Add BluetoothLeBroadcastAssistantCallback." am: bfad455280 am: d89e584952 am: 6b795762eb

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1921059

Change-Id: I44ec395413eeb865a9a5a12a7574fdcff56653ed