Search by ldap_uid when binding as user (#32399)

[oantby]

Pull Request for Issue #32399.

Summary of Changes

Switch from searching by search_string, which is described as not required for bind-as-user, to building a filter based on the ldap_uid attribute laid out in settings.

Testing Instructions

1. Enable LDAP plugin
2. Set to bind directly as the user, and fill out required configuration, leaving search_string blank.
3. set display_errors to On
4. Go to administrative login
5. Attempt to log in as a user who is valid in LDAP, but is not authorized to access Joomla!

Actual result BEFORE applying this Pull Request

Along with the authentication failure message, a php error message is displayed indicating an invalid LDAP filter.

Expected result AFTER applying this Pull Request

Only the intended authentication failure message is displayed.

Documentation Changes Required

None, to my knowledge.

[zero-24]

i will not merge this PR here into 3.10. i see where you are comming from but in oder to keep b/c with the current implementation i will keep it as it is. please sync the setting of the search string with the ldap_uid setting for now that should result into the same behavior.

thanks :-)