bidResponseFilter: IBV not detected on multi-format ad units

[antoine-ga]

The problem

PR #14071 added mediaType enforcement to bidResponseFilter. However, the module checks bid.meta.mediaType against the ad unit's configured mediaTypes and therefore doesn't catch In-Banner Video (IBV) on multi-format ad units.

Proposed fix

Add a comparison between bid.meta.mediaType and bid.mediaType. When both are present and they don't match, the bid should be rejected. This would catch IBV regardless of ad unit configuration.

[antoine-ga]

@robertrmartinez @patmmccann this is what I was mentioning here: #14468 (comment)

[patmmccann]

why would someone want to get rid of ibv on banner responses when the unit allows video?

let's not change the existing behavior, but if pubmatic publishers have a need for this filtering of banner ibv on multiformat units, feel free to add an optional additional filter