### 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
* @param circuitBreakingException CircuitBreakingException thrown
     */
    private void handleCircuitBreakingException(CircuitBreakingException circuitBreakingException) {
        double reducingFactor = Math.min(
            (double) circuitBreakingException.getByteLimit() / circuitBreakingException.getBytesWanted(),
            1 - (Math.log10(pageSize) * 0.1)
        );
        int newPageSize = (int) Math.round(reducingFactor * pageSize);
        if (newPageSize < MINIMUM_PAGE_SIZE) {
            String message = TransformMessages.getMessage(TransformMessages.LOG_TRANSFORM_PIVOT_LOW_PAGE_SIZE_FAILURE, pageSize);
            failIndexer(message);
        } else {
            String message = TransformMessages.getMessage(TransformMessages.LOG_TRANSFORM_PIVOT_REDUCE_PAGE_SIZE, pageSize, newPageSize);
            auditor.info(getJobId(), message);
            logger.info("[{}] {}", getJobId(), message);
            pageSize = newPageSize;
        }
    }
    /**
     * Handle script exception case. This is error is irrecoverable.
     *
     * @param scriptException ScriptException thrown
     */
    private void handleScriptException(ScriptException scriptException) {
        String message = TransformMessages.getMessage(
            TransformMessages.LOG_TRANSFORM_PIVOT_SCRIPT_ERROR,
            scriptException.getDetailedMessage(),
            scriptException.getScriptStack()
        );
        failIndexer(message);