### What?
Optimize the relationship value loading by selecting only the
`useAsTitle` field when fetching document data via the REST API.
### Why?
Previously, all fields were fetched via a POST request when loading the
document data of a relationship value, causing unnecessary data transfer
and slower performance. Only the `useAsTitle` field is needed to display
the related document’s title in the relationship UI field.
### How?
Applied a select to the REST API POST request, similar to how the
options list is loaded, limiting the response to the `useAsTitle` field
only.
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