Summary

This PR addresses the issues highlighted in PR #11707 concerning the incorrect implementation of roleARN support for schedulers.

Problem

The current implementation defaults to using the Lambda function's role, which presents several logical and security concerns:

1. A scheduler should not have the same permission boundaries as the Lambda function itself.
2. Assigning InvokeFunction permissions to the function's role means that the function could potentially call itself—an unintended and potentially dangerous behavior.

Solution

This PR introduces the ability to override the default behavior by allowing roleARN to be explicitly specified, similar to the approach taken by AWS SAM (reference).