[Bug]: Group admin view: missing groups and numbers in sidebar

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

A group admin can see all users that are in at least one of his administered groups under /settings/users.

In the sidebar, there should be all the groups listed where anyone of the shown users is in - including groups that are not administered by said group admin, so that they can filter the list for these groups.

But in the sidebar there are only the groups listed which are administered by said group admin.

Also, the user count for each group is missing.

Steps to reproduce

1. Create some users and some groups
2. Make one of the users group admin of some (but not all) the groups
3. Log in as that group admin user and go to /settings/users

Expected behavior

In the sidebar under /settings/users, there should be all the groups listed where anyone of the shown users is in - including groups that are not administered by said group admin, so that they can filter the list for these groups. Also, the user count for each group in the sidebar should be there.

Nextcloud Server version

32

Additional info

Admin View	Group Admin View

The affected entry point is /settings/users; reproduce with a group admin who belongs to some but not all groups and compare the sidebar with the full admin view. Trace how the sidebar groups and user counts are supplied, then verify that all groups represented by visible users appear with counts and remain filterable.