Elasticsearch will soon restrict users from creating dot indices, only allowing Elastic components to do so.

• Creation of dot indices would be restricted to operators.
• Templates with index patterns that match dot indices would likewise be restricted to operators.

There are 2 areas of the UI today where these interactions are surfaced. We should implement client-side validation that prevents users from entering a dot-prefixed name.

Note: It's worth mentioning that on serverless, this will soon be enforced by default in ES. However, in stateful, a deprecation warning will be logged but it won't be prevented. In Kibana, we won't make this distinction and prevent it on both stateful and serverless.