net/phpldapadmin: update to 1.2.6.4
This includes all the fixes for php81+.
Changes: https://github.com/leenooks/phpLDAPadmin/compare/1.2.6.3...1.2.6.4
PR: 268349
Approved by: rene (mentor)
Differential Revision: https://reviews.freebsd.org/D37700