Credential format and supported algorithm negotiation

As raised on the DCP WG call on the 26th of March, currently the text in OpenID4VP is as follows.

The formats supported by a Verifier may be set up using the metadata parameter vp_formats (see Section 9.1). The Wallet MUST ignore any format property inside a presentation_definition object if that format was not included in the vp_formats property of the metadata.

In essence this establishes that the client metadata takes precedent over the formats element in the presentation definition. HAIP also further re-enforces this with the following text

The presentation of a SD-JWT VC is requested by adding an object named vc+sd-jwt to the format object of an input_descriptor. The object is empty.

I think there is a desire to now instead use the format feature in P.E instead of client metadata. I would prefer we strengthen the language in OpenID4VP to make it clear that the format property of the presentation definition should never be used and instead use only client metadata for this negotiation. Supporting doing the negotiation around this information in two places is likely to create significant confusion.

Start with the cited OpenID4VP Section 9.1 text and the HAIP passage about the vc+sd-jwt format. Review how vp_formats and presentation_definition formats are described, then determine the agreed single negotiation mechanism with the working group. Done means the relevant normative wording clearly reflects that decision.