[Workbench] Suppress "ajax failed" error messages when ajax fails due to browser navigation event.
In fail callbacks, check
status == 'abort' to determine whether the request was terminated by a user action (like navigating away from the current page) rather than an application/network error.
- Show a distinct message like "(cancelled)" that doesn't look like an error, or
- Don't display anything, just clean up internal state and stop.