multiple OpenSearch nodes fail to communicate with each other due to self-signed certs

[mmguero]

Malcolm v25.06.0 added the requirement that the OpenSearch transport protocol must use HTTPS, a requirement that came from using the OpenSearch Security plugin for user/role management.

Malcolm's OpenSearch container generates a self-signed key. As this is only used internally within the Malcolm container cluster and is not exposed anywhere, this is not a big deal. However, a user of the Helm chart reported when deploying with multiple OpenSearch nodes this breaks communication.

There will likely have to be fixes on both the Malcolm side and on the Malcolm-Helm side. See cisagov/Malcolm#757 for the corresponding issue there.