@deleteRecord - onCompleted callback function from commitMutation does not return raw server response

When using `@deleteRecord`, `onCompleted` callback function from commit mutation does not return raw server response, it returns null instead of `id` in my example.

Removing `@deleteRecord` allows to access `id`.

It seems that `onCompleted` callback function is returning store data after mutation instead of raw server response as stated in documentation.

Using react-relay `13.0.1`.

```
const [commit, isInFlightSubmit] = useMutation(graphql`
mutation DeleteCarMutation($id: ID!) {
deleteCar(id: $id) {
id @deleteRecord
}
}
`)
```

```
commit({
variables: {
id: ...,
},
onCompleted: (res) => {
...
},
})
```