[css-images-4][editorial] Added one more WPT

Author: SebastianZ

css-images-4/Overview.bs

@@ -3143,6 +3143,7 @@ Changes Since Level 3</h3>
 <!-- CSS Images 3 tests -->
 <wpt hidden>
 	animation/image-no-interpolation.html
+	animation/object-position-composition.html
 	animation/object-position-interpolation.html
 	animation/object-view-box-interpolation.html
 	animation/image-slice-interpolation-math-functions-tentative.html