BYO MME example notebook failing due to MXNet retirement

[brianloyal]

Link to the notebook
https://github.com/aws/amazon-sagemaker-examples/blob/main/advanced_functionality/multi_model_bring_your_own/multi_model_endpoint_bring_your_own.ipynb

Describe the bug
Running the first code cell in the "Upload model artifacts to S3" section produces an error that reads, "AssertionError: failed to open http://data.mxnet.io/models/imagenet/resnet/18-layers/resnet-18-0000.params". Browsing to https://mxnet.apache.org, I see that the project was retired in September 2023.

To reproduce
Run the notebook in a SageMaker Notebook Instance

Logs

AssertionError Traceback (most recent call last)
Cell In[7], line 7
3 import tarfile
5 model_path = "http://data.mxnet.io/models/imagenet/"
----> 7 mx.test_utils.download(
8 model_path + "resnet/18-layers/resnet-18-0000.params", None, "data/resnet_18"
9 )
10 mx.test_utils.download(
11 model_path + "resnet/18-layers/resnet-18-symbol.json", None, "data/resnet_18"
12 )
13 mx.test_utils.download(model_path + "synset.txt", None, "data/resnet_18")

File ~/anaconda3/envs/python3/lib/python3.10/site-packages/mxnet/test_utils.py:1812, in download(url, fname, dirname, overwrite, retries)
1810 retries -= 1
1811 if retries <= 0:
-> 1812 raise e
1814 print("download failed, retrying, {} attempt{} left"
1815 .format(retries, 's' if retries > 1 else ''))
1816 logging.info("downloaded %s into %s successfully", url, fname)

File ~/anaconda3/envs/python3/lib/python3.10/site-packages/mxnet/test_utils.py:1803, in download(url, fname, dirname, overwrite, retries)
1801 try:
1802 r = requests.get(url, stream=True)
-> 1803 assert r.status_code == 200, "failed to open %s" % url
1804 with open(fname, 'wb') as f:
1805 for chunk in r.iter_content(chunk_size=1024):

AssertionError: failed to open http://data.mxnet.io/models/imagenet/resnet/18-layers/resnet-18-0000.params