Gravity Forms Help Scout Addon 2.3.0

- Added the "Click here to refresh access token" button to the add-on settings page so the request can be attempted again when it times out.
- Updated logging statements to clarify that the add-on is still connected to Help Scout when the token refresh times out.

- Updated authentication logging statements.
- Updated Javascript files, stylesheets to use minified versions.
- Fixed auth token refresh failing when the add-on is using a custom app.

- Fixed conversation creation failing when the last name is not provided for a new customer