add CHANGES.md entry for async/await test conversion

Author: zoran995

CHANGES.md

@@ -8,6 +8,7 @@
 - Underline text buttons
 - Replace node-fetch with node native fetch.
 - Refactor tests to use @testing-library/react instead of react-test-renderer and react-shallow-testutils, and remove deprecated libraries. (#7755, #7763)
+- Convert test `done` callbacks to async/await for modern test patterns.
 - [The next improvement]
 
 #### 8.11.3 - 2026-02-02