Add getPackageName to VoiceInteractor

Adds a new API to VoiceInteractor to allow apps to query
the package name of the Voice Interactor associated with
this the current voice interaction

BUG: 192061561
CTS-Coverage-Bug: 218687104
Test: Manual validation from personal and work profiles

Change-Id: If381c38498535bf94d13c0b5ad5f6c4fa5495117