As reported in https://github.com/localstack/localstack/issues/6659#issuecomment-1630932643_, `HeadObject` does not respect `ChecksumMode`. 


```shell
at 09:31:57 ➜ AWS_DEFAULT_REGION=us-west-1 aws --endpoint-url=http://localhost:4566 s3api create-bucket --bucket test-bucket --create-bucket-configuration LocationConstraint=us-west-1
{
    "Location": "http://test-bucket.s3.localhost.localstack.cloud:4566/"
}

at 09:32:13 ➜ aws --endpoint-url=http://localhost:4566 s3api put-object --bucket test-bucket --key file.json --body README.md --checksum-algorithm SHA256
{
    "ETag": "\"4bb2f1387449d690bff6336ea255909c\"",
    "ChecksumSHA256": "bzOikXXMUqRTCrpVq7Pt7LjJ0fjR3ccUfM19S/gnfqA="
}

# SHA256 missing here
at 09:32:20 ➜ aws --endpoint-url=http://localhost:4566 s3api head-object --bucket test-bucket --key file.json --checksum-mode Enabled
{
    "AcceptRanges": "bytes",
    "LastModified": "2023-07-11T13:32:15+00:00",
    "ContentLength": 1455,
    "ETag": "\"4bb2f1387449d690bff6336ea255909c\"",
    "ContentType": "binary/octet-stream",
    "Metadata": {}
}
```

Note the equivalent response from S3 actual includes the SHA256 value

```shell
at 10:21:23 ➜ aws s3api head-object --bucket test-bucket --key file.json --checksum-mode Enabled
{
    "AcceptRanges": "bytes",
    "Expiration": "expiry-date=\"Thu, 13 Jul 2023 00:00:00 GMT\", rule-id=\"all\"",
    "LastModified": "2023-07-11T14:21:09+00:00",
    "ContentLength": 1956,
    "ChecksumSHA256": "bj7fqCqtaF95M1ULwQRDJuHbL/Xd9NVMH6pua9OINcc=",
    "ETag": "\"f4be535d45019a4408dd5369986919f8\"",
    "ContentEncoding": "",
    "ContentType": "binary/octet-stream",
   
    "Metadata": {},
    
}
```

_Originally posted by @bdurrani in https://github.com/localstack/localstack/issues/6659#issuecomment-1630932643_
            
data = f"""
            <Delete xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
              <Object>
                <Key>{_key_1}</Key>
              </Object>
              <Object>
                <Key>{_key_2}</Key>
              </Object>
            </Delete>
            """
        md = hashlib.md5(data.encode("utf-8")).digest()
        contents_md5 = base64.b64encode(md).decode("utf-8")
        header = {"content-md5": contents_md5, "x-amz-request-payer": "requester"}
        r = .post(url=url, data=data, headers=header)
        assert 200 == r.status_code
        response = xmltodict.parse(r.content)
        # TODO
        if LEGACY_S3_PROVIDER:
            response["DeleteResult"].pop("@xmlns")
        snapshot.match("multi-delete-with-", response)
        response = aws_client.s3.list_s(Bucket=bucket_name)
        snapshot.match("list-remaining-s", response)
    @pytest.mark.aws_validated
    @pytest.mark.skip_snapshot_verify(
        paths=[
            "$..Prefix",
        ]
    )
    @pytest.mark.skip_snapshot_verify(condition=is_old_provider, path="$..Deleted..VersionId")
    def test_s3_batch_delete_s(self, s3_bucket, snapshot, aws_client):