fixup! refactor(material-experimental/mdc-list): no longer use deprecated styles

Remove high contrast styles

Author: devversion

src/material-experimental/mdc-list/list.scss

@@ -71,34 +71,3 @@
 .mat-mdc-list-item.mdc-list-item--with-trailing-meta > .mdc-list-item__end:empty {
   display: none;
 }
-
-@include a11y.high-contrast(active, off) {
-  .mat-mdc-list-option,
-  .mat-mdc-nav-list .mat-mdc-list-item,
-  .mat-mdc-action-list .mat-mdc-list-item {
-    &:hover, &:focus {
-      outline: dotted 1px;
-    }
-  }
-
-  // In single selection mode, the selected option is indicated by changing its
-  // background color, but that doesn't work in high contrast mode. We add an
-  // alternate indication by rendering out a circle.
-  .mat-mdc-list-option.mdc-list-item--selected::after {
-    $size: 10px;
-    content: '';
-    position: absolute;
-    top: 50%;
-    right: mdc-list-variables.$side-padding;
-    transform: translateY(-50%);
-    width: $size;
-    height: 0;
-    border-bottom: solid $size;
-    border-radius: $size;
-  }
-
-  [dir='rtl'] .mat-mdc-list-option.mdc-list-item--selected::after {
-    right: auto;
-    left: mdc-list-variables.$side-padding;
-  }
-}