### 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
);
        request.allowPartialSearchResults(false) 
            .indicesOptions(IndicesOptions.LENIENT_EXPAND_OPEN); 
        changeCollector.buildChangesQuery(sourceBuilder, position != null ? position.getBucketsPosition() : null, pageSize);
        QueryBuilder queryBuilder = getConfig().getSource().getQueryConfig().getQuery();
        TransformConfig config = getConfig();
        BoolQueryBuilder filteredQuery = new BoolQueryBuilder().filter(queryBuilder)
            .filter(config.getSyncConfig().getRangeQuery(lastCheckpoint, nextCheckpoint));
        
        sourceBuilder.query(filteredQuery);
        logger.debug("[{}] Querying {} for changes: {}", getJobId(), request.indices(), sourceBuilder);
        return request.source(sourceBuilder);
    }
    private SearchRequest buildQueryToUpdateDestinationIndex() {
        TransformIndexerPosition position = getPosition();
        TransformConfig config = getConfig();
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder().runtimeMappings(getConfig().getSource().getRuntimeMappings());
        function.buildSearchQuery(sourceBuilder, position != null ? position.getIndexerPosition() : null, pageSize);
        SearchRequest request = new SearchRequest();
        QueryBuilder queryBuilder = config.getSource().getQueryConfig().getQuery();
        if (isContinuous()) {
            BoolQueryBuilder filteredQuery = new BoolQueryBuilder().filter(queryBuilder)
                .filter(config.getSyncConfig().getRangeQuery(nextCheckpoint));
            
            if (nextCheckpoint.getCheckpoint() > 1 && changeCollector != null) {
                QueryBuilder filter = changeCollector.buildFilterQuery(lastCheckpoint, nextCheckpoint);
                if (filter != null) {
                    filteredQuery.filter(filter);
                }
                /*