RecurringEdit - Add example. Include test assertions. Fix undeclared/missing properties.

RecurringEdit - Add example. Include test assertions. Fix undeclared/missing properties.

This creates a new example of the `RecurringEdit` workflow message.

Note that the example is tagged `phpunit` and defines a list of `asserts`. These
assertions are evaluated using the default message-template.

The test was not passing because some important properties were missing from `RecurringEdit`.