### Elasticsearch Version

main

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

MacOS

### Problem Description

When there are 2 or more concurrent `_update` requests issued, one of them may fail with `ResourceAlreadyExistsException` exception which is misleading.


### Steps to Reproduce

1. Spawn a number of `_update` requests at the same time
2. Look at the results of these requests
3. Observe `ResourceAlreadyExistsException` being thrown in the case of conflict

### Logs (if relevant)

_No response_
x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/persistence/IndexBasedTransformConfigManager.java
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.DocWriteRequest;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexAction;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
import org.elasticsearch.action.admin.indices.refresh.RefreshRequest;
import org.elasticsearch.action.admin.indices.refresh.RefreshResponse;
import org.elasticsearch.action.bulk.BulkItemResponse;
import org.elasticsearch.action.index.IndexAction;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.search.SearchAction;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.support.IndicesOptions;
import org.elasticsearch.action.support.WriteRequest;
import org.elasticsearch.client.internal.Client;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.regex.Regex;
import org.elasticsearch.common.util.concurrent.ThreadContext;
import org.elasticsearch.common.util.set.Sets;
import org.elasticsearch.common.xcontent.LoggingDeprecationHandler;
import org.elasticsearch.core.TimeValue;
import org.elasticsearch.core.Tuple;
import org.elasticsearch.index.IndexNotFoundException;
import org.elasticsearch.index.engine.VersionConflictEngineException;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilder;