[python] Attempting to print an ApplicationEvent raises a NameError

In an earlier release of the product, the code that displays `ApplicationEvents` in human-readable form referenced a non-existent field in the `ApplicationEvent` object. This meant that attempting to print or log the value of an `ApplicationEvent` triggered an exception that can cause the application to exit unexpectedly in error. In this release, the reference to the non-existent field has been removed and the human readable output has been adjusted to remove any visible reference to it As a result, the `ApplicationEvent` may now be referenced in a log or print statement without raising an unexpected error.