Bug: Curation Item Field Always Returns Null

## Summary

The `item` field in the `curations` query always returns `null`, even though every curation should have an associated item according to the data model.

## Expected Behavior

When querying curations with the `item` field, it should return the associated item object with its properties (id, metadata, etc.).

## Actual Behavior

The `item` field consistently returns `null` for all curations, regardless of the actual data relationships.

## GraphQL Query Example

```graphql
{
curations {
id
timestamp
curator {
id
}
item {
id
blockchainId
metadata {
wearable {
name
}
emote {
name
}
}
}
}
}
```

## Quick Test with cURL

You can reproduce this issue immediately with the following command:

```bash
curl -X POST \
-H "Content-Type: application/json" \
-d '{"query":"{ curations(first: 5) { id timestamp item { id blockchainId } } }"}' \
https://subgraph.decentraland.org/collections-matic-mainnet
```

**Expected Result:** Each curation should have an `item` object with `id` and `blockchainId`
**Actual Result:** All curations have `item: null`

## Environment

- **Subgraph URL:** `https://subgraph.decentraland.org/collections-matic-mainnet`
- **Network:** Polygon (Matic)

## Impact

This bug prevents applications from:

1. Accessing individual item details during curation queries
2. Properly linking curations to their associated items