### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When multi uploading a file for Glacier Instant Retrieval, the operation fails at Complete stage with a message claiming storage class not supported.

### Expected Behavior

It works with real S3.

### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

localstack start

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

 ```golang
	b, p := parse1(path)
	cmuI := &awsS3.CreateMultipartUploadInput{
		Bucket:       b,
		Key:          p,
		StorageClass: mtypes.StorageClassGlacierIr,
	}
_, err := client.CreateMultipartUpload(context.Background(), cmuI)

```
and process the upload of the part and then complete

### Environment

```markdown
- OS: Ubuntu 20.04
- LocalStack: pro latest
```


### Anything else?

_No response_
Bucket=s3_bucket, Key=_key, ExpiresIn=60
        )
        # modi
        original_policy = presigned_request["fields"]["policy"]
        presigned_request["fields"]["policy"] = original_policy[:-2]
        response = .post(
            presigned_request["url"],
            data=presigned_request["fields"],
            files={"file": "file content"},
            verify=False,
        )
        # the 
        exception = xmltodict.parse(response.content)
        exception["StatusCode"] = response.status_code
        snapshot.match("exception-policy", exception)
        # asse
        signature_field = "signature" if signature_version == "s3" else "x-amz-signature"
        assert (
            exception["Error"]["SignatureProvided"] == presigned_request["fields"][signature_field]
        )
        assert exception["Error"]["StringToSign"] == presigned_request["fields"]["policy"]
    @pytest.mark.aws_validated
    @pytest.mark.xfail(
        condition=LEGACY_S3_PROVIDER, reason="Signature is not validated in legacy provider"
    )
    @pytest.mark.parametrize(
        "signature_version",
        ["s3", "s3v4"],
    )
    def test_post_request_missing_signature(