[Bug]: No UserChangedEvent emitted for LDAP users that are disable via markRemnantsAsDisabled config

⚠️ 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

Normally, when a user is being disabled or enabled, a UserChangedEvent is being emitted. There are listeners that consume this change. One example is the dav app, which updates the system addressbook and removes disabled users and re-add re-enabled users.

Now when the LDAP configuration's setting markRemnantsAsDisabled is set to 1 then all remnants users are reported as disabled, but the event is not being emitted at any time. And so components that act on stored information, like the system addressbook, do not have the information and still show that user in the contactsmenu.

Steps to reproduce

1. Have an LDAP confguration
2. Modify the config per cli (it is not exposed so far): occ ldap:set-config s01 markRemnantsAsDisabled 1
3. Delete a users on LDAP
4. Ensure the user is known as deleted: occ ldap:check-user $USERID
5. In the web interface, look in the contacts menu for this user

Expected behavior

The user does not show up in the results

Installation method

None

Nextcloud Server version

master

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

Affected are 28-master