
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/AttributeMap.java
for (Entry<AttributeWrapper, E> entry : smaller.delegate.entrySet()) {
            if (larger.delegate.containsKey(entry.getKey())) {
                intersect.delegate.put(entry.getKey(), entry.getValue());
            }
        }
        return intersect;
    }
    public boolean subsetOf(AttributeMap<E> other) {
        if (this.size() > other.size()) {
            return false;
        }
        for (AttributeWrapper aw : delegate.keySet()) {
            if (other.delegate.containsKey(aw) == false) {
                return false;
            }
        }
        return true;
    }
    public Set<String> attributeNames() {
        Set<String> s = Sets.newLinkedHashSetWithExpectedSize(size());
        for (AttributeWrapper aw : delegate.keySet()) {
            s.add(aw.attr.name());
        }
        return s;
    }
    @Override
    public int size() {
        return delegate.size();
    }
    @Override