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/TransportPreviewTransformAction.java
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.logging.HeaderWarning;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentHelper;
import org.elasticsearch.common.xcontent.support.XContentMapValues;
import org.elasticsearch.ingest.IngestService;
import org.elasticsearch.license.License;
import org.elasticsearch.license.RemoteClusterLicenseChecker;
import org.elasticsearch.tasks.Task;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.TransportService;
import org.elasticsearch.xcontent.ToXContent;
import org.elasticsearch.xcontent.XContentBuilder;
import org.elasticsearch.xcontent.XContentFactory;
import org.elasticsearch.xcontent.XContentType;
import org.elasticsearch.xpack.core.ClientHelper;
import org.elasticsearch.xpack.core.XPackSettings;
import org.elasticsearch.xpack.core.common.validation.SourceDestValidator;
import org.elasticsearch.xpack.core.security.SecurityContext;
import org.elasticsearch.xpack.core.transform.TransformField;
import org.elasticsearch.xpack.core.transform.action.PreviewTransformAction;
import org.elasticsearch.xpack.core.transform.action.PreviewTransformAction.Request;
import org.elasticsearch.xpack.core.transform.action.PreviewTransformAction.Response;
import org.elasticsearch.xpack.core.transform.transforms.SourceConfig;
import org.elasticsearch.xpack.core.transform.transforms.SyncConfig;
import org.elasticsearch.xpack.core.transform.transforms.TransformConfig;
import org.elasticsearch.xpack.core.transform.transforms.TransformDestIndexSettings;
import org.elasticsearch.xpack.transform.persistence.TransformIndex;