Integrate voice assistant into flutter-ics-homescreen

Integrate voice assistant into flutter-ics-homescreen

 - Implement voice-agent client to connect with agl-service-voiceagent
   for command execution, wake word detection.
 - ⁠Add a setting tile on the settings page for configuring voice
   assistant settings.
 - Add toggle buttons for wake word mode, online mode, overlay and
   speech-to-text model in the voice assistant settings.
 - Add a button on the homepage to start the voice assistant.
 - Update gRPC protos to retrieve online-mode status from the voice
   service.
 - Make online-mode tile conditional in voice-assistant settings,
   removing it from the UI if not enabled in the service.
 - Automatically hide the overlay 3 seconds after command execution.

Bug-AGL: SPEC-5200
Change-Id: I4efaaf16ebc570b28816dc7203364efe2b658c2e
Signed-off-by: Anuj Solanki <anuj603362@gmail.com>