### 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_
import time
import pytest
import requests
from boto3.s3.transfer import KB, TransferConfig
from botocore.exceptions import ClientError
from localstack import config
from localstack.utils.collections import is_sub_dict
from localstack.utils.strings import short_uid
class TestS3:
    @pytest.mark.aws_validated
    @pytest.mark.skip_snapshot_verify(paths=["$..EncodingType"])
    def test_region_header_exists(self, s3_client, s3_create_bucket, snapshot):
        snapshot.add_transformer(snapshot.transform.s3_api())
        bucket_name = s3_create_bucket(
            CreateBucketConfiguration={"LocationConstraint": "eu-west-1"},
        )
        response = s3_client.head_bucket(Bucket=bucket_name)
        assert response["ResponseMetadata"]["HTTPHeaders"]["x-amz-bucket-region"] == "eu-west-1"
        snapshot.match("head_bucket", response)
        response = s3_client.list_objects_v2(Bucket=bucket_name)
        assert response["ResponseMetadata"]["HTTPHeaders"]["x-amz-bucket-region"] == "eu-west-1"
        snapshot.match("list_objects_v2", response)
    @pytest.mark.aws_validated
    @pytest.mark.skip_snapshot_verify(paths=["$..Marker", "$..Prefix", "$..EncodingType"])
    def test_delete_bucket_with_content(self, s3_client, s3_resource, s3_bucket, snapshot):