List Meta pixels

Lists the pixels on the ad account with the time each one last received an event, and the standard events it has recently recorded where Meta exposes them. Use when: setting up a sales or leads campaign — those objectives cannot optimise without a pixel and an event — or when diagnosing why conversions are not being recorded. Do not treat a pixel that exists as a pixel that works: a pixel with no recent fire time will not deliver conversions no matter what the campaign says. Returns the pixel id needed by meta_create_image_campaign and the event names that are safe to optimise for. If no pixel has fired recently, tell the user that a conversion campaign will not optimise and suggest a traffic objective instead.