dropdown_list_widget: Do not underline the option text on focus.

We remove the underline on the text in the options on focus as
we already have a outline which is enough to show that the option
is focussed.

web/styles/settings.css

@@ -1584,6 +1584,10 @@ $option_title_width: 180px;
                     hsl(200deg 100% 35%)
                 );
             }
+
+            &:focus {
+                text-decoration: none;
+            }
         }
     }
 }