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_
            
Conditions=[{"bucket": s3_bucket}, ["eq", "$success_action_status", "201"]],
            ExpiresIn=60,
        )
        files = {"file": ("my-file", body)}
        response = .post(
            presigned_request["url"],
            data=presigned_request["fields"],
            files=files,
            verify=False,
        )
        assert response.status_code == 201
        json_response = xmltodict.parse(response.content)
        assert "PostResponse" in json_response
        json_response = json_response["PostResponse"]
        if LEGACY_S3_PROVIDER and not is_aws_cloud():
            # lega
            location = "http://localhost/key-my-file"
            etag = "d41d8cd98f00b204e9800998ecf8427f"
        else:
            location = f"{_bucket_url_vhost(s3_bucket, aws_stack.get_region())}/key-my-file"
            etag = '"43281e21fce675ac3bcb3524b38ca4ed"'
            assert response.headers["ETag"] == etag
            assert response.headers["Location"] == location
        assert json_response["Location"] == location
        assert json_response["Bucket"] == s3_bucket
        assert json_response["Key"] == "key-my-file"
        assert json_response["ETag"] == etag
    @pytest.mark.aws_validated
    @pytest.mark.xfail(condition=LEGACY_S3_PROVIDER, reason="not supported in legacy provider")
    def test_s3_presigned_post_success_action_redirect(self, s3_bucket, aws_client):