[Seq2Seq Example : Access denied error when downloading pretrained model from AWS S3 bucket ]

**Link to the notebook**
[Add the link to the notebook.](https://github.com/aws/amazon-sagemaker-examples/tree/main/introduction_to_amazon_algorithms/seq2seq_translation_en-de)

**Describe the bug**
When downloading the pretrained model from the AWS S3 bucket , I get an access denied error on the bucket

**To reproduce**
A clear, step-by-step set of instructions to reproduce the bug.

use_pretrained_model = True
model_name = "example-model"
!curl https://s3-us-west-2.amazonaws.com/seq2seq-data/model.tar.gz > model.tar.gz
!curl https://s3-us-west-2.amazonaws.com/seq2seq-data/vocab.src.json > vocab.src.json
!curl https://s3-us-west-2.amazonaws.com/seq2seq-data/vocab.trg.json > vocab.trg.json
upload_to_s3(bucket, prefix, 'pretrained_model', 'example.tar.gz')
model_data = "s3://{}/{}/pretrained_model/example.tar.gz".format(bucket, prefix)

**Logs**
If applicable, add logs to help explain your problem.
You may also attach an `.ipynb` file to this issue if it includes relevant logs or output.

ClientError: An error occurred (AccessDenied) when calling the ListObjectsV2 operation: Access Denied

Open the Seq2Seq translation notebook at introduction_to_amazon_algorithms/seq2seq_translation_en-de and inspect the pretrained-model download commands for seq2seq-data/model.tar.gz and the vocabulary files. Reproduce the curl download and subsequent upload_to_s3/model_data flow, then verify that the pretrained model can be downloaded and used without the reported S3 AccessDenied error.

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