Fix double-delegation of graphql requests to worker threads.

[npomaroli]

This also fixes possible unnecessary queueing of graphql requests, since the removed "inner" delegation was done "ordered".

Abstract

Checklist

General

• Added abstract that describes the change
• Added changelog entry to /CHANGELOG.adoc
• Ensured that the change is covered by tests
• Ensured that the change is documented in the docs

On API Changes

• Checked if the changes are breaking or not
• Added GraphQL API if applicable
• Added Elasticsearch mapping if applicable