fix(checkbox): Remove GPU layer promotion for mark elements

This commit removes the CSS that promotes checkmarks to the GPU layer,
due to an issue in Chrome which makes transitions appear incorrect when
the promotions are applied.

src/components/checkbox/checkbox.scss

@@ -202,9 +202,7 @@ $_md-checkbox-indeterminate-checked-easing-function: cubic-bezier(0.14, 0, 0, 1)
  */
 %md-checkbox-mark {
   $width-padding-inset: 2 * $md-checkbox-border-width;
-
   width: calc(100% - #{$width-padding-inset});
-  will-change: opacity, transform;
 }
 
 /**