Removes .card-shadow in cards/_borderless.scss

Author: fredtitao

src/scss/cards/_borderless.scss

@@ -8,9 +8,6 @@
         border-top: 0 none;
       }
     }
-    &-shadow {
-      box-shadow: $card-box-shadow;
-    }
     &-list {
       display: flex;
       flex-wrap: wrap;