Update Step Functions Parent ID Generation

[avedmala]

Updates the parent ID generation using upstream Step Functions context object to be able to handle retries

Old behavior would result in the same parent ID for all retries, this new behavior will use the retry_count when it's non-zero. This way we don't break backwards compatibility with old layers that don't use this value in the common case of redrive_count:0

Related: DataDog/datadog-lambda-python#559

Motivation

Testing Guidelines

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
• This PR passes the integration tests (ask a Datadog member to run the tests)

[nine5two7]

LGTM