E-mail does not get sent if Form Spreadsheet does not exist

[hecerinc]

If there isn't a Spreadsheet associated with the Form, the e-mail will not send, and there is no validation of this in the code or instructions to create one in the Quickstart Guide.

I would like to patch this (as per the Contribution Guide) by creating the form on installation of the add-on (script run) or validating that it exists on the code.