Fix incorrect user count

[Sebastianmueller22]

Summary

Just a simple check if the limit is exceeded it adds a plus. Tested with a system with that many users in a subgroup and it showed up correctly.

Resolves #54878

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

[CarlSchwan]

This will change the return type in the frontend, not sure what are the consequence of that

[Sebastianmueller22]

It didn't produce any issue in my test. I looked for usages and it seems to be handled in a type agnostic way. I did it in oder to not have the limit hard coded in the frontend as well.

I could alternatively send the limit with the response and make the check in the frontend. Should I do that instead?

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