Support retrieving partial responses from endpoints (refactor for pydantic `2.10`)

Endpoint such as searches allow providing a parameters called `fields` which is an `enum` of fields which the response ends up returning e.g `href, id, name, type, division, serverDisplayName, notes`

> The string must not contain any spaces. Just alphanumerics, underscores, commas, and dots.

This would mean we would have to make all fields in our `Response` objects optional.

We should also validate that the input is in fact an acceptable response field name.