Fix Course List pattern not working with newest Gutenberg version

[m1r0]

Part of #7873

Proposed Changes

• Related to this Gutenberg change (and the following fix), patterns are now required to be wrapped in a Query block. This PR fixes that for the Course List pattern (course-grid-with-background).

Testing Instructions

1. Check-out this Gutenberg PR.
2. Test the Course List block and make sure the Course List pattern is working as expected.

Pre-Merge Checklist

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

[m1r0]

It's normal for the E2E tests to be failing because the suite is not using the latest Gutenberg.