
Filing this issue to track a question/comment that was raised by @ywangd  here https://github.com/elastic/elasticsearch/pull/98309#discussion_r1294115440

One question I do have is why we chose to [execute the LookupRequest with the enrich origin](https://github.com/elastic/elasticsearch/blob/2e4440ff1c0decf79f8a40688566411f7d518aa7/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/enrich/EnrichLookupService.java#L141C2-L141C2). It means the following query works when the user has access to only the playlist index without access to either the songs enrich policy or its associated index.

```
FROM playlist | ENRICH songs ON song_id
```

It feels a bit weird to me that we have no control on who can use what enrich process. That said, we don't have a good story around enrich and ingest pipeline either, i.e. we have no control over who can use what pipeline where a pipeline can contain an enrich processor. There have been quite a few complaints from users and we have an https://github.com/elastic/elasticsearch/issues/57586 for it. I wonder whether we should not repeat the problem here with ES|QL. On the surface, it might be easier to tackle compared to ingest pipelines since ES|QL is read-only and has no "bulk" operations. What do you think?
x-pack/plugin/ql/src/main/java/org/elasticsearch/xpack/ql/expression/AttributeSet.java
delegate = new AttributeMap<>();
            for (Attribute a : attr) {
                delegate.add(a, PRESENT);
            }
        }
    }
    private AttributeSet(AttributeMap<Object> delegate) {
        this.delegate = delegate;
    }
    
    
    void addAll(AttributeSet other) {
        delegate.addAll(other.delegate);
    }
    public AttributeSet combine(AttributeSet other) {
        return new AttributeSet(delegate.combine(other.delegate));
    }
    public AttributeSet subtract(AttributeSet other) {
        return new AttributeSet(delegate.subtract(other.delegate));
    }
    public AttributeSet intersect(AttributeSet other) {
        return new AttributeSet(delegate.intersect(other.delegate));
    }
    public boolean subsetOf(AttributeSet other) {
        return delegate.subsetOf(other.delegate);
    }
    public Set<String> names() {
        return delegate.attributeNames();
    }
    @Override