Fix learning mode template navigation buttons

[richardlhr]

Resolves #
This updaet fixes some of the Lesson actions that are not ADA compliant.

Proposed Changes

• Remove duplicate hidden previous and next links
• Adding a Previous Button to facilitate Navigation from the Main section
• Adding role=button to links and role=status to Completed Button
• Adding 2 unit test fr the Previous Button
• Fix error when running npm test

Testing Instructions

1. Create a Default Course with 3 lessons.
2. Enroll to the course and navigate to the first lesson. There should not be navigation buttons
3. Complete the First Lesson.
4. The Next Button should appear. The Completed Button should have role=status and there should be a Next Lesson Button
5. Click the Next Lesson Button. There should now be a Previous Lesson Button

New/Updated Hooks

Deprecated Code

Pre-Merge Checklist

• [X ] PR title and description contain sufficient detail and accurately describe the changes
• [ X] Adheres to coding standards (PHP, JavaScript, CSS, HTML)
• [ X] All strings are translatable (without concatenation, handles plurals)
• [ X] Follows our naming conventions (P6rkRX-4oA-p2)
• [ X] Hooks (p6rkRX-1uS-p2) and functions are documented
• [ X] New UIs are responsive and use a mobile-first approach
• [ X] Code is tested on the minimum supported PHP and WordPress versions