feat(NotificationSetting): Add trafficSource field

[danbillson]

Adds the trafficSource types to notification settings for create, update and list

Usage:

  const ntfSet = await paddle.notificationSettings.create({
    description: "Test Notification Setting",
    destination: "https://your.app/webhook",
    subscribedEvents: ["address.created"],
    type: "url",
    trafficSource: "simulation",
  });