[ILM] Backing indices of hidden data streams don't have ilm policy information

[yuliacech]

Kibana version:
Current master

Describe the bug:
Found when testing 87960
When a hidden data stream is created and an ILM policy is attached to it, its backing indices should have this information in Index Management plugin. Currently, ILM policy information is not loaded. Possibly a similar fix as in 87960 (changing * to .*) when fetching ILM information here could work.

Steps to reproduce:

1. Create an ILM policy with this command in Dev Tools console

PUT /_ilm/policy/my-data-stream-policy
{
  "policy": {
    "phases": {
      "hot": {
        "actions": {
          "rollover": {
            "max_size": "25GB"
          }
        }
      }
    }
  }
}

2. Create an index template for a hidden data stream using the ILM policy

PUT /_index_template/my-data-stream-template
{
  "index_patterns": [ "my-data-stream*" ],
  "data_stream": {
    "hidden": true
  },
  "priority": 200,
  "template": {
    "settings": {
      "index.lifecycle.name": "my-data-stream-policy"
    }
  }
}

3. Index a document

POST /my-data-stream/_doc/
{
  "@timestamp": "2020-12-06T11:04:05.000Z"
}

4. Navigate to Stack Management -> Index Lifecycle Policies and click Actions -> View indices linked to policy on the created my-data-stream-policy
5. After redirecting to Index Management, Indices list will not show the corresponding indices.

Expected behavior:
When using View linked indices action, Index Management correctly shows indices.

Screenshots (if relevant):

Possible fix
This information is loaded via an ILM data enricher (see this file) and we could add expand_wildcards=hidden,all to the "explain lifecycle" request but this could potentially cause more performance issues with the indices list loading times (related issue).

[elasticmachine]

Pinging @elastic/es-ui (Team:Elasticsearch UI)