Gracefully handle unnecessary omissions

[coltenkrauter]

There may be cases where folks setup their GitHub token or Slack token with more restrictive permissions. Determine which logic is not required to carry out the purpose of this project and allow it to fail gracefully.

Definition of Done

• Implement error handling for cases where permissions are missing or users fail to match.
• Ensure the system does not crash or generate unhandled exceptions during these omissions.
• Provide clear, user-friendly error messages or logs when these situations occur.