Using the same user count as in user:report

[MorrisJobke]

It would be good to have the same user counts as in user:report.

server info basically only counts users that have logged in (and maybe weren't cleaned up properly):

https://github.com/nextcloud/serverinfo/blob/8487657cc105c43fcf620a38ef8990be2016c3ce/lib/StorageStatistics.php#L58-L65

The user:report counts by user backend:

https://github.com/nextcloud/server/blob/caff1023ea72bb2ea94130e18a2a6e2ccf819e5f/lib/public/IUserManager.php#L149-L155

https://github.com/nextcloud/server/blob/7506cbb1c4a3f48d21c3ace6bee705aad2e1f91a/core/Command/User/Report.php#L61-L74