### 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
TransformInternalIndexConstants.INDEX_NAME_PATTERN_DEPRECATED
        );
        deleteByQueryRequest.setQuery(
            QueryBuilders.constantScoreQuery(
                QueryBuilders.boolQuery()
                    .mustNot(QueryBuilders.termQuery("_index", TransformInternalIndexConstants.LATEST_INDEX_NAME))
                    .filter(QueryBuilders.termQuery("_id", TransformStoredDoc.documentId(transformId)))
            )
        );
        executeAsyncWithOrigin(
            client,
            TRANSFORM_ORIGIN,
            DeleteByQueryAction.INSTANCE,
            deleteByQueryRequest,
            ActionListener.wrap(response -> {
                if ((response.getBulkFailures().isEmpty() && response.getSearchFailures().isEmpty()) == false) {
                    Tuple<RestStatus, Throwable> statusAndReason = getStatusAndReason(response);
                    listener.onFailure(
                        new ElasticsearchStatusException(statusAndReason.v2().getMessage(), statusAndReason.v1(), statusAndReason.v2())
                    );
                    return;
                }
                listener.onResponse(response.getDeleted());
            }, listener::onFailure)
        );
    }
    @Override
    public void deleteOldCheckpoints(String transformId, long deleteCheckpointsBelow, long deleteOlderThan, ActionListener<Long> listener) {
        DeleteByQueryRequest deleteByQueryRequest = createDeleteByQueryRequest();
        deleteByQueryRequest.indices(