chore: Fix a stack in snapshot tests

[lym953]

Motivation

correct-lambda-function-stack-legacy-datadog-api-snapshot.json is empty. This is because the stack should be called lambda-function-stack-legacy-datadog-api, but it is lambda-function-stack from copy-paste.

What does this PR do?

Updates the stack name, so a snapshot can be created with the correct name.

Testing Guidelines

The snapshot becomes not empty.

Additional Notes

Types of Changes

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

Check all that apply

• 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