fix(chat) removed unread msgs counter on chat open

react/features/chat/components/web/ChatCounter.js

     /**
      * The value of to display as a count.
      */
-    _count: number
+    _count: number,
+
+    /**
+     * True if the chat window should be rendered.
+     */
+    _isOpen: boolean
 };
 
 /**
     render() {
         return (
             <span className = 'badge-round'>
+
                 <span>
-                    { this.props._count || null }
+                    {
+                        !this.props._isOpen
+                        && (this.props._count || null)
+                    }
                 </span>
             </span>
         );
  * }}
  */
 function _mapStateToProps(state) {
+    const { isOpen } = state['features/chat'];
+
     return {
-        _count: getUnreadCount(state)
+        _count: getUnreadCount(state),
+        _isOpen: isOpen
     };
 }