Allow admin to be registered as a participatory space user (#6890)

[armandfardeau]

🎩 What? Why?

Backport allow admin to be registered as a participatory space user by removing faulty lines from a previous pull request.

📌 Related Issues

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• Related to Allow admin to be registered as a participatory space user #6890
• Fixes Problem when adding an admin as a private user #6869

Testing

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📋 Checklist

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• ❓ CONSIDER adding a unit test if your PR resolves an issue.
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• ❌AVOID breaking the continuous integration build.
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📷 Screenshots

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