Mark body of archival_config endpoint as required

[arpad-m]

As pointed out in #8414 (comment)

Part of #8088

[github-actions]

3126 tests run: 3005 passed, 0 failed, 121 skipped (full report)

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Code coverage* (full report)

• functions: 32.6% (7000 of 21466 functions)
• lines: 50.0% (55275 of 110580 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
4e1f746 at 2024-07-22T15:30:11.719Z :recycle:}