A preview call can be quite expensive and cause timeout in a cluster. As a short term fix we identified 2 (hopefully) small fixes:

- make the call cancellable, the main issue here seems to be that preview calls search without using a parent task id(see this fix for data feeds: https://github.com/elastic/elasticsearch/pull/88142/files#diff-aba58244cb8f9dfa3ac3b6efeb02259e3d5956576f56c1ff5e243dd2aac27381)
- pass the timeout parameter of the preview call to the search call, currently a timeout can be specified, but is ignored for the inner search call, which is executed with no timeout (see https://www.elastic.co/guide/en/elasticsearch/reference/master/search-search.html#search-search-api-query-params).

Both changes are bugs and shall be relatively simple to implement and considered for backport to the 7.17 branch.

@przemekwitek can you have a look at this?

related: #88010
x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/action/TransportValidateTransformAction.java
import org.elasticsearch.xpack.core.transform.TransformDeprecations;
import org.elasticsearch.xpack.core.transform.TransformMessages;
import org.elasticsearch.xpack.core.transform.action.ValidateTransformAction;
import org.elasticsearch.xpack.core.transform.action.ValidateTransformAction.Request;
import org.elasticsearch.xpack.core.transform.action.ValidateTransformAction.Response;
import org.elasticsearch.xpack.core.transform.transforms.TransformConfig;
import org.elasticsearch.xpack.transform.transforms.Function;
import org.elasticsearch.xpack.transform.transforms.FunctionFactory;
import org.elasticsearch.xpack.transform.transforms.TransformNodes;
import org.elasticsearch.xpack.transform.utils.SourceDestValidations;
import java.util.Map;
import static org.elasticsearch.core.Strings.format;
public class TransportValidateTransformAction extends HandledTransportAction<Request, Response> {
    private final Client client;
    private final ClusterService clusterService;
    private final TransportService transportService;
    private final Settings nodeSettings;
    private final SourceDestValidator sourceDestValidator;
    @Inject
    public TransportValidateTransformAction(
        TransportService transportService,
        ActionFilters actionFilters,
        Client client,
        IndexNameExpressionResolver indexNameExpressionResolver,
        ClusterService clusterService,
        Settings settings,
        IngestService ingestService
    ) {
        super(ValidateTransformAction.NAME, transportService, actionFilters, Request::new);
        this.client = client;