[BUG] Cannot include hidden indices

Describe the bug
Indices are searched using /_cat/indices?format=json, which means hidden indices can never be included.

To Reproduce

Create an hidden index in OpenSearch:

PUT /my-hidden-index
{
  "settings": {
    "index.hidden": "true"
  }
}

Write any pipeline that tries to include that index:

# ...
indices:
  include:
    - index_name_regex: "my-hidden-index"
# ...

See the logs saying that no indices matched:

DEBUG org.opensearch.client.RequestLogger - request [GET http://opensearch:9200/_cat/indices?format=json] returned [HTTP/1.1 200 OK]
DEBUG org.opensearch.dataprepper.plugins.source.opensearch.worker.OpenSearchIndexPartitionCreationSupplier - Found 9 indices
WARN  org.opensearch.dataprepper.plugins.source.opensearch.worker.OpenSearchIndexPartitionCreationSupplier - No indices matched the configured regex patterns after applying include/exclude filters

Expected behavior
It should be able to include hidden indices just like it can already include system-indices.

For backwards compatibility, this could be an opt-in flag (e.g., include_hidden: true).

Start with OpenSearchIndexPartitionCreationSupplier and trace the request to /_cat/indices?format=json. Run the supplied hidden-index and pipeline reproduction, then verify that the configured hidden index can be matched while existing behavior remains compatible, including any opt-in setting selected by the maintainers.