In T417797 wbui2025 was updated to render HTML API errors when available: Gerrit change
This works, but it is effectively duck typing and leaks knowledge of the internal error structure into UI code. As suggested in code review, this logic should live on ErrorObject instead.
Acceptance Criteria
- Extend ErrorObject with a method such as getErrorHtml()
- Add related helpers if required
- Have callers check for ErrorObject and use its methods instead of reading nested fields directly
- Update tests
