### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

The Complete Multipart Upload operation generates the **InternalError** error for non-existing uploads.

### Expected Behavior

The Complete Multipart Upload operation generates the **NoSuchUpload** error for non-existing uploads.

### How are you starting LocalStack?

With a `docker run` command

### Steps To Reproduce

    docker run -it --rm -p 4566:4566 localstack/localstack

    aws s3api create-bucket --bucket test --endpoint-url http://localhost:4566 --create-bucket-configuration LocationConstraint=us-west-2

    aws s3api complete-multipart-upload --bucket test --endpoint-url http://localhost:4566 --key test --upload-id test

### Environment

```markdown
- OS: Windows 11
- LocalStack: latest
```


### Anything else?

The Abort Multipart Upload operation works correctly in LocalStack.

The official documentation: https://docs.aws.amazon.com/AmazonS3/latest/API/API_CompleteMultipartUpload.html
Amazon S3 throws the correct **NoSuchUpload** error for both Abort and Complete operations.
self, context: RequestContext, bucket: BucketName, body: IO[Body] = None
    ) -> PostResponse:
        
        
        
        validate_post_policy(context.request.form)
        
        
        
        try:
            response: PostResponse = call_moto(context=context)
        except ServiceException as e:
            if e.status_code == 303:
                
                response = PostResponse(StatusCode=e.status_code)
            else:
                raise e
        key_name = context.request.form.get("key")
        if "${filename}" in key_name:
            key_name = key_name.replace("${filename}", context.request.files["file"].filename)
        moto_backend = get_moto_s3_backend(context)
        
        key = get_key_from_moto_bucket(
            get_bucket_from_moto(moto_backend, bucket=bucket), key=key_name
        )