Cascader: update cascader style (#13596)

packages/cascader/src/menu.vue

@@ -285,7 +285,7 @@
               id = { itemId }
               aria-owns = { !item.children ? null : ownsId }
             >
-              {item.label}
+              <span>{item.label}</span>
             </li>
           );
         });

packages/theme-chalk/src/cascader.scss

@@ -129,6 +129,11 @@
     box-sizing: border-box;
     cursor: pointer;
     outline: none;
+
+    span {
+      padding-right: 10px;
+    }
+
     @include m(extensible) {
       &:after {
         font-family: 'element-icons';