fix(user_ldap): Pass `LDAP_ESCAPE_FILTER` for filters to be used with…

[solracsf]

… ldap_search()

• Resolves:

https://help.nextcloud.com/t/attempt-for-paging-bad-search-filter/185970/2

Summary

This step ensures that any special characters in the $filter (such as parentheses, asterisks, or backslashes) are properly escaped before performing the LDAP search.

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
• [x] Backports requested where applicable (ex: critical bugfixes)