style: remove bg-color of menu items at ':focus' state in vertical mode (#2659)

packages/theme-chalk/src/menu.scss

@@ -38,6 +38,9 @@
   &:hover,
   &:focus {
     outline: none;
+  }
+
+  &:hover {
     background-color: var(--el-menu-item-hover-fill);
   }
 
@@ -86,6 +89,9 @@
       &:focus,
       &:hover {
         outline: none;
+      }
+
+      &:hover {
         .#{$namespace}-submenu__title {
           color: var(--el-color-text-primary);
         }
@@ -189,6 +195,10 @@
           transform: none;
         }
       }
+
+      &.is-active i {
+        color: var(--el-color-primary);
+      }
     }
   }
   @include m(popup) {