### Description

Currently, when we execute retention policy, we also refresh the destination index by setting:
```
setRefresh(true)
```
on the DBQ request.
This can cause permission errors which are surprising to the user as the permissions are not required when the transform starts:
```
task encountered irrecoverable failure: org.elasticsearch.ElasticsearchSecurityException: action [indices:admin/refresh] is unauthorized for user [found-internal-kibana4-server] with roles [kibana_system,found-internal-kibana4-server] on indices [logs-cloud_security_posture.findings_latest-default], this action is granted by the index privileges [maintenance,manage,all]
```

We still want the user to have the permissions to delete the documents. But we should execute `refresh` as the system user.
x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/transforms/TransformIndexer.java
if (latch.await(PERSIST_STOP_AT_CHECKPOINT_TIMEOUT_SEC, TimeUnit.SECONDS) == false) {
                    logger.error(
                        () -> format(
                            "[%s] Timed out (%ss) waiting for transform state to be stored.",
                            getJobId(),
                            PERSIST_STOP_AT_CHECKPOINT_TIMEOUT_SEC
                        )
                    );
                }
                
                if (newtaskState.equals(TransformTaskState.STOPPED)) {
                    context.shutdown();
                }
                return false;
            }
            if (state != IndexerState.INDEXING) {
                return false;
            }
            if (saveStateListeners.updateAndGet(currentListeners -> {
                
                
                
                if (getState() != IndexerState.INDEXING) {
                    return null;
                }
                if (currentListeners == null) {
                    
                    if (context.shouldStopAtCheckpoint() == shouldStopAtCheckpoint) {
                        return null;
                    }