Batch get campaign status

Returns the status (lifecycle state) and deliveryStatus (whether the campaign is currently serving), along with deliveryStatusReasons, for up to 100 campaigns in a single call. This is the recommended way to poll the review and serving state of many campaigns at once. Provide the campaign IDs in campaignIds; any ID that is not found or is not owned by the caller is returned in the failures array with reason NOT_FOUND.