fix(dropdown): fix rounded corners on scrolling menu

On a filtered dropdown menu the bottom corners are not round. This PR makes all corners of the dropdown menu round.

Author: grandeljay

src/definitions/modules/dropdown.less

@@ -1335,7 +1335,7 @@ select.ui.dropdown {
     overflow-y: auto;
     border: none;
     box-shadow: none !important;
-    border-radius: 0 !important;
+    border-radius: 0 0 @floatingMenuBorderRadius @floatingMenuBorderRadius !important;
     margin: 0 !important;
     min-width: 100% !important;
     width: auto !important;
@@ -1550,9 +1550,6 @@ select.ui.dropdown {
     box-shadow: @floatingMenuBoxShadow !important;
     border-radius: @floatingMenuBorderRadius !important;
   }
-  .ui.floating.dropdown > .menu {
-    border-radius: @floatingMenuBorderRadius !important;
-  }
   .ui:not(.upward).floating.dropdown > .menu {
     margin-top: @floatingMenuDistance;
   }