Xml.name set uncessarly for some nested object

```tsp
model Author {
@attribute id: string;
book?: Book;
}

model Book {}

```

produce
```yaml
Author:
type: object
required:
- id
properties:
id:
type: string
xml:
attribute: true
book:
allOf:
- $ref: '#/components/schemas/Book'
xml:
name: book
```

[Playground Link](https://typespec.io/playground/?e=%40typespec%2Fopenapi3&c=aW1wb3J0ICJAdHlwZXNwZWMveG1sIjsKCnVzaW5nIFhtbDsKCm1vZGVsIEF1dGhvciB7CiAgQGF0dHJpYnV0ZSBpZDogc3RyaW5nOwogIGJvb2s%2FOiBCb29rOwp9yDrEDyB7fQo%3D&options=%7B%7D&vs=%7B%7D)