replaces deprecated clip rule with recommended clip-path alternative.

from https://developer.mozilla.org/en-US/docs/Web/CSS/clip:
> Warning: Authors are encouraged to use the clip-path property instead.

Author: stopfstedt

packages/ilios-common/app/styles/ilios-common/mixins/visually-hidden.scss

@@ -1,6 +1,6 @@
 @mixin visually-hidden {
   border: 0;
-  clip: rect(0 0 0 0);
+  clip-path: rect(0 0 0 0);
   height: 1px;
   margin: -1px;
   overflow: hidden;