This PR introduced https://github.com/payloadcms/payload/pull/11952
improvement for graphql schema with making fields of the `Paginated<T>`
interface non-nullable.
However, there are a few special ones - `nextPage` and `prevPage`. They
can be `null` when:
The result returned 0 docs.
The result returned `x` docs, but in the DB we don't have `x+1` doc.
Thus, `nextPage` will be `null`. The result will have `nextPage: null`.
Finally, when we query 1st page, `prevPage` is `null` as well.
<img width="873" alt="image"
src="https://github.com/user-attachments/assets/04d04b13-ac26-4fc1-b421-b5f86efc9b65"
/>