fix(modal): add transparent outline for high contrast themes (#5037)

Author: emyarod

packages/components/src/components/modal/_modal.scss

@@ -75,6 +75,9 @@
     width: 100%;
     height: 100%;
     max-height: 100%;
+    // make modal edge visible on high contrast themes (#3880)
+    outline: 3px solid transparent;
+    outline-offset: -3px;
     overflow: hidden;
     transform-origin: top center;
     transform: translate3d(0, -24px, 0);