test: Fix Terraform Docker container

[valerena]

Terraform Docker container was trying to use python3.9 on AL2, which doesn't exist. Migrate to AL2023, which already has python3.9 installed (so we don't even need to install it)

Which issue(s) does this change fix?

Why is this change necessary?

How does it address the issue?

What side effects does this change have?

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.