Fix loading state

windows/ReactNativeWebView/ReactWebViewManager.cpp

                     {
                         WriteProperty(eventDataWriter, L"canGoBack", webView.CanGoBack());
                         WriteProperty(eventDataWriter, L"canGoForward", webView.CanGoForward());
-                        WriteProperty(eventDataWriter, L"loading", false);
+                        WriteProperty(eventDataWriter, L"loading", true);
                         WriteProperty(eventDataWriter, L"target", tag);
                         WriteProperty(eventDataWriter, L"title", webView.DocumentTitle());
                         WriteProperty(eventDataWriter, L"url", uri.ToString());