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
private Object result;
        Response(Object result) {
            this.result = result;
        }
        Response(StreamInput in) throws IOException {
            super(in);
            result = in.readGenericValue();
        }
        public Object getResult() {
            return result;
        }
        @Override
        public void writeTo(StreamOutput out) throws IOException {
            out.writeGenericValue(result);
        }
        @Override
        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
            builder.startObject();
            builder.field("result", result);
            return builder.endObject();
        }
        @Override
        public boolean equals(Object o) {
            if (this == o) return true;