style: make arrows in usergroup members selector easier to press

rhodecode/public/css/main-content.less

@@ -353,7 +353,12 b''
         .middle-group{
             width: 10%;
             text-align: center;
-            padding-top: 6em;
+            padding-top: 4em;
+            i {
+                font-size: 18px;
+                cursor: pointer;
+                line-height: 2em;
+            }
         }
 
     }