chore: Untrack duplicate test snapshots from git

[lym953]

Motivation

Right now, two identical snapshots are created for each stack used by integration tests. For example, lambda_python_stack.py has:

• correct-lambda_python_stack-snapshot.json
• test-lambda_python_stack-snapshot.json

The "test" one is supposed to be used locally and not supposed to be committed to git.

What does this PR do?

Remove the "test" snapshots from Git.

Testing Guidelines

aws-vault exec sso-serverless-sandbox-account-admin -- scripts/run_integration_tests.sh still works.

Additional Notes

test-lambda-function-stack-legacy-datadog-api-snapshot.json is empty, which is unexpected. I will take a look and fix it in another PR.

Types of Changes

• [ ] Bug fix
• [ ] New feature
• [ ] Breaking change
• [x] Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• [x] This PR's description is comprehensive
• [ ] This PR contains breaking changes that are documented in the description
• [ ] This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• [ ] This PR impacts documentation, and it has been updated (or a ticket has been logged)
• [ ] This PR's changes are covered by the automated tests
• [ ] This PR collects user input/sensitive content into Datadog