Add an ID to the sidebar channel more (#6399)

* Add an ID to the sidebar channel more

For UI Automation

* Add an ID to the Create New Channel button

webapp/components/sidebar.jsx

@@ -852,6 +852,7 @@ export default class Sidebar extends React.Component {
                         {publicChannelItems}
                         <li>
                             <a
+                                id='sidebarChannelsMore'
                                 href='#'
                                 className='nav-more'
                                 onClick={this.showMoreChannelsModal}