Making use of prefers-reduced-motion media query (#25641)

* Making use of `prefers-reduced-motion` media query

As discussed in #25249 - if a user (Who is using Safari / iOS) requests
reduced motion in their system settings, we should avoid transitions.

* Ignoring prefers reduced motion for CSS Linting
* Updating copy clarifying the reduce motion functionality in accessibility.md

scss/mixins/_transition.scss

@@ -6,4 +6,8 @@
       transition: $transition;
     }
   }
+
+  @media screen and (prefers-reduced-motion: reduce) {
+    transition: none;
+  }
 }