Trying to hit the [execute API](https://www.elastic.co/guide/en/elasticsearch/painless/8.5/painless-execute-api.html) with an index that in available via cross cluster search will fail with an `IllegalArgumentException`: `Cross-cluster calls are not supported in this context but remote indices were requested`

That is because `PainlessExecuteAction`'s [`TransportAction`](https://github.com/elastic/elasticsearch/blob/8.5/modules/lang-painless/src/main/java/org/elasticsearch/painless/action/PainlessExecuteAction.java#L462) is a [`TransportSingleShardAction`](https://github.com/elastic/elasticsearch/blob/8.5/server/src/main/java/org/elasticsearch/action/support/single/shard/TransportSingleShardAction.java#L153) which uses [`IndexNameExpressionResolver.concreteIndices`](https://github.com/elastic/elasticsearch/blob/8.5/server/src/main/java/org/elasticsearch/cluster/metadata/IndexNameExpressionResolver.java#L331), which does not support remote clusters.

What would it take it enable PainlessExecuteAction to support CCS?

Kibana uses the execute api to validate runtime fields on edit, see https://github.com/elastic/kibana/issues/145861
modules/lang-painless/src/main/java/org/elasticsearch/painless/action/PainlessExecuteAction.java
Request::new,
                ThreadPool.Names.MANAGEMENT
            );
            this.scriptService = scriptService;
            this.indicesServices = indicesServices;
        }
        @Override
        protected Writeable.Reader<Response> getResponseReader() {
            return Response::new;
        }
        @Override
        protected ClusterBlockException checkRequestBlock(ClusterState state, InternalRequest request) {
            if (request.concreteIndex() != null) {
                return super.checkRequestBlock(state, request);
            }
            return null;
        }
        @Override
        protected boolean resolveIndex(Request request) {
            return request.contextSetup != null && request.contextSetup.getIndex() != null;
        }
        @Override
        protected ShardsIterator shards(ClusterState state, InternalRequest request) {
            if (request.concreteIndex() == null) {
                return null;
            }
            return state.routingTable().index(request.concreteIndex()).randomAllActiveShardsIt();
        }