feat: add v5.6.0 package updates

[onesignal-deploy]

Release v5.6.0

🐛 Bug Fixes

• fix: correct update_subscription_by_token examples and gate C# enum precedence on missing spec example
• fix: restore ApiException prototype on ES5 + extend Python create_notification hero catch
• fix: drop dead pprint import from python create_notification hero

📚 Docs

• docs: enrich spec with example: values on path/query params
• docs: add idiomatic error-handling stubs to DefaultApi.md examples
• docs: demonstrate polymorphic response handling for POST /notifications
• docs: fix polymorphic createNotification example correctness across SDKs

---

Generated from OneSignal/api-client-libraries@3b35d43...f69765a.

[onesignal-deploy]

Superseded by v5.6.0 release.