Sizeless placement multiplex banners

For multiplex, we only use one size in the request. This reduces complexity interacting with the spreadsheet. Currently using 970x250 because it multiplexes to a lot of sizes.

Configure a placement as sizeless in PubMaestro by setting the placement size to "Non-standard/Fluid Size".

A placement is considered enhanced if in PubMaestro one of its creative type is "clickout".

Display ad - Unenhanced 970x250

Placeholder to replace with ad script

Display ad - Enhanced 970x250

Placeholder to replace with ad script

Display ad - Enhanced/unenhanced 970x250

Placeholder to replace with ad script