### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

There is an issue with `get-object-attributes` command which results in below error always: 
`aws --endpoint-url=http://localhost:4566 s3api get-object-attributes --bucket s3mock --key 20.txt --object-attributes "ObjectSize"`
````

> Response:  Unable to parse response (syntax error: line 1, column 0), invalid XML received. Further retries may succeed:
b'98\n5\n'
````

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### Using docker-compse.yaml to start localstack

docker-compse.yaml:

```
localstack:
    image: localstack/localstack:latest
    ports:
      - '4563-4599:4563-4599'
      - '8055:8080'
    environment:
      - SERVICES=s3
      - DEBUG=1
      - LS_LOG=error
      - DATA_DIR=/tmp/localstack/data
      - AWS_DEFAULT_REGION=eu-west-1
      # - EDGE_PORT=4566
    volumes:
      - "./.localstack:/tmp/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"
```

#### cli commands to reproduce the issue

1. Create a Bucket: `aws --endpoint-url=http://localhost:4566 s3 mb s3://s3mock`
2. Create an Object: `aws --endpoint-url=http://localhost:4566 s3 cp data/20.txt s3://s3mock`

File 20.txt content are 2-digit numbers separated by newline.

3. get-object-attributes for object 20.txt :
```

 aws --endpoint-url=http://localhost:4566 s3api get-object-attributes --bucket s3mock --key 20.txt --object-attributes "ObjectSize"

```
Results in error:

> Unable to parse response (syntax error: line 1, column 0), invalid XML received. Further retries may succeed:
b'98\n5\n'



### Environment

```markdown
- OS:Mac 12.x
- LocalStack:latest
- Node 14
```


### Anything else?

_No response_
if uri_param_name in uri_params:
                    payload = uri_params[uri_param_name]
            else:
                raise UnknownParserError("Unknown shape location '%s'." % location)
        else:
            # If we don't have to use a specific location, we use the node
            payload = node
        fn_name = "_parse_%s" % shape.type_name
        handler = getattr(self, fn_name, self._noop_parser)
        try:
            n handler(request, shape, payload, uri_params) if payload is not None else None
        except (TypeError, ValueError, AttributeError) as e:
            raise ProtocolParserError(
                f"Invalid type when parsing {shape.name}: '{payload}' cannot be parsed to {shape.type_name}."
            ) from e
    # The parsing functions for primitive types, lists, and timestamps are shared among subclasses.
    def _parse_list(
        self,
        request: HttpRequest,
        shape: ListShape,
        node: list,
        
    ):
        parsed = []
        member_shape = shape.member
        for item in node:
            parsed.append(self._parse_shape(request, member_shape, item, uri_params))
        n parsed
    @_text_content
    def _parse_integer(self, _, __, node: str, ___) -> int: