websocket close connection with error code

in `WebsocketAPI` can we have a method that closes a websocket connection with a specified code?

[similar to this](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/close)

according to the websocket protocol we should be able to do this -> [spec](https://www.rfc-editor.org/rfc/rfc6455.html#section-7.4)

right now, in API gateway logs, the connection is always closed with status code 1000 when calling the existing `close` method:

```python3
app.websocket_api.close(event.connection_id)
```

API gateway logs:
```
Endpoint request body after transformations:
...
{
"routeKey": "$disconnect",
"disconnectStatusCode": 1000,
"authorizer": {
"principalId": "user"
},
"eventType": "DISCONNECT",
"requestTime": "20/Jul/2023:23:29:25 +0000",
"messageDirection": "IN",
"disconnectReason": "Connection Closed Normally",
"connectedAt": 1689895754759,
"requestTimeEpoch": 1689895765983,
...
```

Start at the WebsocketAPI entry point and inspect the existing close(event.connection_id) call described in the issue. Compare its behavior with the linked WebSocket close documentation and API Gateway logs; done means callers can provide a close code and API Gateway reports that code instead of always reporting 1000.

Written by the indexing model from the issue text.