Is your feature request related to a problem? Please describe.
OpenSearch data source plugin doesn't allow querying remote indexes when using OpenSearch cross cluster search feature - when trying to use remote index, like remote_cluster:index-name, I get 404 error in UI.

Describe the solution you'd like
I would like OpenSearch data source plugin to be able to retrieve data from remote cluster(s).

Describe alternatives you've considered
ElasticSearch plugin supports it - grafana/grafana#72353. I've succeeded to use it with my OpenSearch cluster but I don't think it's much future-proof.

Additional context
Screenshot with index name configuration and error: