Render a template publication

Renders one immutable publication against the data you pass, formatted in the locale and timeZone you name as a send formats them, and returns the subject, preheader, HTML and plain text a send would produce. data is validated against the publication's input schema exactly as a send validates it; invalid input returns a validation error that names each failing field. Nothing is sent or stored. Unpublished workspace edits are never rendered: only a publication id renders.