fixed user-menu dropdown top border

build/scss/_dropdown.scss

@@ -185,7 +185,6 @@
   > .dropdown-menu {
     @include border-top-radius(0);
     padding: 0;
-    border-top-width: 0;
     width: 280px;
 
     &,

dist/css/adminlte.css

@@ -13017,7 +13017,6 @@ body.text-sm .control-sidebar {
   border-top-left-radius: 0;
   border-top-right-radius: 0;
   padding: 0;
-  border-top-width: 0;
   width: 280px;
 }