Remove unused constant

What does this MR do?

This just removes an unused constant.

What are the relevant issue numbers?

No issue, spotted by @DouweM, faster to fix than create an issue.

Does this MR meet the acceptance criteria?

• [-] Changelog entry added, if necessary
• [-] Documentation created/updated
• [-] Tests added for this feature/bug
• [-] Conforms to the code review guidelines
• [-] Conforms to the merge request performance guidelines
• [-] Conforms to the style guides
• [-] Conforms to the database guides