CurlDispatcher timeout should be caught and rather not crash the page

This particular exception happens when a YouTube video is no longer available or private, which is a very common situation.

The crash can be temporarily fixed in ConvertUrlToEmbedFilter.php as shown in the snippet below, although it's really only a first attempt at getting past the road block. Please excuse the misplaced use of a Bootstrap alert here. You certainly know a better way to inject a message to make end users aware of a problem with one of the URLs in the text.

 public function process($text, $langcode) {
    try {
      $result = new FilterProcessResult(static::convertUrls($text, $this->settings['url_prefix']));
    }
    catch (NetworkException $e) {
      $result = new FilterProcessResult('<p class="alert alert-danger">A network exception occurred with embedding an URL</p> ' . $text);
    }
    return $result;
  }