### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

`#return` macro for AppSync is not supported

```
- ["Error in template '<string>' at position 48-60 in expression: #return($v1)\nException: no such macro: return\n\nGraphQL request:3:11\n2 |         {\n3 |           hi2 {\n  |           ^\n4 |             value"] None
```

### Expected Behavior

`#return` is a valid command in AppSync Resolver Velocity request and response templates.

https://docs.aws.amazon.com/appsync/latest/devguide/aws-appsync-directives.html 

### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    localstack start

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

1. `CDKDeployment`
2. GraphQL Rest API to `localstack`

3. AppSync resolver with response template:

```vtl
#set($v1 = {})
$util.qr($v1.put('value', 'hi'))
#return($v1)"
```

```sdl
schema {
  query: Query
}
type valueObj {
  value: String
}
type Query {
  hi2: valueObj
}
```

4. Query AppSync

```sdl
Query {
   hi2
}
```



### Environment

```markdown
- OS: Ubuntu/WSL2
- LocalStack: 0.14.2.1
```


### Anything else?

The same code runs fine on AWS/AppSync.
"""
    Handles response template rendering
    """
    def render(self, api_context: ApiInvocationContext):
        response = api_context.response
        integration = api_context.integration
        
        
        
        api_context.data = response._content
        int_responses = integration.get("integrationResponses") or {}
        if not int_responses:
            return response._content
        entries = list(int_responses.keys())
        return_code = str(response.status_code)
        if return_code not in entries and len(entries) > 1:
            LOG.info("Found multiple integration response status codes: %s", entries)
            return response._content
        return_code = entries[0]
        response_templates = int_responses[return_code].get("responseTemplates", {})
        template = response_templates.get(APPLICATION_JSON, {})
        if not template:
            return response
        variables = self.build_variables_mapping(api_context)
        response._content = self.render_vtl(template, variables=variables)
        LOG.info("Endpoint response body after transformations:\n%s", response._content)
        return response._content