Get apiv1email sequences

Handles the retrieval of all campaign messages (email sequences) for a specified campaign associated with the authenticated user.

Raises: JsonResponse: 400 status code if the campaign_uid query parameter is missing or invalid. JsonResponse: 404 status code if the campaign does not exist or the user lacks access.

Required Query Parameters: campaign_uid: UID of the campaign to fetch email sequences from.

Returns: JsonResponse: A response with a list of serialized campaign messages, containing the total count of messages and their details.