Fixing DM separator and margin on system console (#2944)

Fixing margins on system console

webapp/components/admin_console/setting.jsx

@@ -5,7 +5,7 @@ import React from 'react';
 
 export default class Setting extends React.Component {
     render() {
-        let marginClass;
+        let marginClass = '';
         if (this.props.margin === 'small') {
             marginClass = ' form-group--small';
         }

webapp/sass/layout/_sidebar-left.scss

@@ -16,9 +16,10 @@
         color: $white;
         font-size: .9em;
         height: 20px;
-        margin: 5px 0 6px;
         line-height: 20px;
+        margin: 5px 0 6px;
         position: relative;
+        z-index: 0;
 
         &:before {
             background: $light-gray;