### 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.
if not is_aws_cloud() and not LEGACY_S3_PROVIDER:
            monkeypatch.setattr(config, "S3_SKIP_SIGNATURE_VALIDATION", False)
        src_key = "src"
        aws_client.s3.put_(Bucket=s3_bucket, Key=src_key, Body="something")
        # copy 
        dest_key = "dest"
        response = aws_client.s3.copy_(
            Bucket=s3_bucket,
            CopySource={"Bucket": s3_bucket, "Key": src_key},
            Key=dest_key,
        )
        snapshot.match("copy-obj", response)
        # Crea
        dest_key2 = "dest"
        url = s3_presigned_client.generate_presigned_url(
            "copy_",
            Params={
                "Bucket": s3_bucket,
                "CopySource": {"Bucket": s3_bucket, "Key": src_key},
                "Key": dest_key2,
            },
        )
        request_response = .put(url, verify=False)
        assert request_response.status_code == 200
    @pytest.mark.only_localstack
    @pytest.mark.parametrize("case_sensitive_headers", [True, False])
    def test_s3_get_response_case_sensitive_headers(