fix(wizards): include path for `wizards.assets.php`

[jaredrethman]

All Submissions:

• [x] Have you followed the Newspack Contributing guideline?
• [x] Does your code follow the WordPress' coding standards and VIP Go coding standards?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Fixes warning: "include(/Users/raz/Sites/newspack/plugin/includes/wizards/build/wizards.asset.php): Failed to open stream: No such file or directory in /Users/raz/Sites/newspack/plugin/includes/wizards/class-wizard.php on line 151"

How to test the changes in this Pull Request:

Other information:

• [x] Have you added an explanation of what your changes do and why you'd like us to include them?
• [ ] Have you written new tests for your changes, as applicable?
• [x] Have you successfully ran tests with your changes locally?

[matticbot]

:tada: This PR is included in version 4.2.0-epic-ia.2 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: