refactor: streamline background streaming service and notification handling

- Updated BackgroundStreamingService to use a minimal notification for foreground service, enhancing clarity and compliance with Android requirements.
- Removed redundant notification updates and logging statements in VoiceCallService to improve code readability and maintainability.
- Adjusted notification channel settings for better background service management.

lib/features/chat/services/voice_call_notification_service.dart

@@ -99,12 +99,9 @@ class VoiceCallNotificationService {
     required bool isSpeaking,
   }) async {
     if (!_initialized) {
-      print('VoiceCallNotification: Initializing...');
       await initialize();
     }
 
-    print('VoiceCallNotification: Showing notification for $modelName (muted: $isMuted, speaking: $isSpeaking)');
-
     final status = isSpeaking ? 'Speaking...' : 'Listening...';
     final muteAction = isMuted ? 'Unmute' : 'Mute';
     final muteActionId = isMuted ? _actionUnmute : _actionMute;