Invalid class in response to an undocumented response.

`ApiRequestor->handleApiError()` references the class `CleverInvalidRequest`, but that class is not defined anywhere. Suspect it's intending to reference `CleverInvalidRequestError`, but the signatures don't match. It's also attempting to catch a response (402) that [the documentation](https://clever.com/developers/docs#guide-getting-started-api-responses-section) does not list as a possible response from the API. Further, NONE of the other Clever-supplied libraries are attempting to catch this response type.