fix: update AirbyteTracedException.__str__ to show user-facing message (AI-Triage PR) (#927)

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: bot_apk <apk@cognition.ai>
Co-authored-by: sophie.cui@airbyte.io <sophie.cui@airbyte.io>