OGCAPI-Records 406 reesponse for schema.org/dcat/geojson

A number of formats don't work (406) via the ogcapi-records endpoint for collections and items.

Works

- https://sdi.eea.europa.eu/catalogue/api/collections/main/items?f=html
- https://sdi.eea.europa.eu/catalogue/api/collections/main/items?f=json
- https://sdi.eea.europa.eu/catalogue/api/collections/main/items?f=xml
- https://sdi.eea.europa.eu/catalogue/api/collections/main/items?f=rss

406

- https://sdi.eea.europa.eu/catalogue/api/collections/main/items?f=geojson
- https://sdi.eea.europa.eu/catalogue/api/collections/main/items?f=schema.org
- https://sdi.eea.europa.eu/catalogue/api/collections/main/items?f=dcat
- https://sdi.eea.europa.eu/catalogue/api/collections/main/items/4f796d29-db1e-4145-949e-95dd37ae7f78?f=dcat_turtle

Might just need to check content type the app is trying to send back for these requests, and see if its included in the accept header"

`Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,/;q=0.8,application/signed-exchange;v=b3;q=0.7`

Reproduce the 406 responses on the ogcapi-records collection and item URLs for geojson, schema.org, dcat, and dcat_turtle, and compare them with the working formats. Start by inspecting content negotiation around the endpoint and the request Accept header. Done means those formats return their intended representations instead of 406 responses, with regression coverage where the endpoint tests are located.

Written by the indexing model from the issue text.