Resolves #7400.

Proposed Changes

Replaces get_class calls with __CLASS__ magic constant.

Testing Instructions

1. Switch to PHP 8.3+.
2. Activate Sensei.
3. Ensure there are no PHP get_class deprecation notices.

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