TF-3699 Thread Detail Next previous actions (#3843)

core/lib/presentation/views/html_viewer/html_content_viewer_widget.dart

@@ -360,6 +360,7 @@ class HtmlContentViewState extends State<HtmlContentViewer> with AutomaticKeepAl
   void dispose() {
     _loadingBarNotifier.dispose();
     _htmlData = null;
+    _webViewController.dispose();
     super.dispose();
   }