docs: Improve AWS supplier samples

[aeitzman]

No description provided.

[snippet-bot]

Here is the summary of changes.

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• samples/cloud-client/snippets/authenticate_with_aws_supplier.py:15, tag auth_cloud_aws_supplier

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[conventional-commit-lint-gcf]

🤖 I detect that the PR title and the commit message differ and there's only one commit. To use the PR title for the commit history, you can use Github's automerge feature with squashing, or use automerge label. Good luck human!

-- conventional-commit-lint bot
https://conventionalcommits.org/

[parthea]

samples/cloud-client/snippets/snippets_test.py needs to be updated to call authenticate_with_aws_supplier to add this to the existing samples presubmit tests

[parthea]

Switching to draft while review comments are being addressed

[chalmerlowe]

@aeitzman I appreciate you submitting this PR and I understand that it has been a long time.
If you are interested in having this merged and your schedule allows, Google requires a CLA.

I will hold off on moving forward until Tuesday, Jan 20th @ Noon (EST). I know this is a short turn around, my apologies. At that time, we will close out this PR so that we can prep to migrate this repo into the google-cloud-auth mono-repo.