### 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_
"""Change casing of Last-Modified and other headers to be picked by the parser"""
        status_code, resp_headers, key_value = fn(self, *args, **kwargs)
        for low_case_header in [
            "last-modified",
            "content-type",
            "content-length",
            "content-range",
            "content-encoding",
            "content-language",
            "content-disposition",
            "cache-control",
        ]:
            if header_value := resp_headers.pop(low_case_header, None):
                header_name = capitalize_header_name_from_snake_case(low_case_header)
                resp_headers[header_name] = header_value
        
        
        bucket_key_enabled = "x-amz-server-side-encryption-bucket-key-enabled"
        if val := resp_headers.get(bucket_key_enabled, ""):
            resp_headers[bucket_key_enabled] = str(val).lower()
        return status_code, resp_headers, key_value
    @patch(moto_s3_responses.S3Response._bucket_response_head)
    def _fix_bucket_response_head(fn, self, bucket_name, *args, **kwargs):
        code, headers, body = fn(self, bucket_name, *args, **kwargs)
        bucket = self.backend.get_bucket(bucket_name)
        headers["x-amz-bucket-region"] = bucket.region_name
        headers["content-type"] = "application/xml"
        return code, headers, body
    @patch(moto_s3_responses.S3Response._key_response_get)
    def _fix_key_response_get(fn, *args, **kwargs):