message: Removed enforcement of as_user field
diff: @@ -340,9 +340,6 @@ export class SlackAdapter extends BotAdapter {
  message.user = activity.recipient.id;
  }
  - if (message.icon_url || message.icon_emoji || message.username) {
  - message.as_user = false;
  - }
  return message;
  }
  