Support IPv6 for LDAP connections (#12882)

* Support IPv6 for LDAP connections

Adds support for IPv6 LDAP connections. The underlying clj-ldap library
requires a different format of the host parameter to support IPv6.

IPv6 addresses must be wrapped in [], like:
[2601:600:967f:88d4:b476:56a8:c364:94da]

Converted the LDAP expect tests to clojure.test also.

Resolves #12879

* Update LDAP IPv6 test to handle CircleCI not supporting IPv6

Co-authored-by: Cam Saul <github@camsaul.com>