Issue #3300969 by deulenko, phenaproxima: Passing null to parameter #1...

Issue #3300969 by deulenko, phenaproxima: Passing null to parameter #1 ($haystack) of type string is deprecated

lightning_media.module

@@ -384,7 +384,7 @@ function lightning_media_js_settings_alter(array &$settings) {
   }
 
   $route_name = \Drupal::routeMatch()->getRouteName();
-  if (strpos($route_name, 'entity_browser') === 0 && isset($settings['ajaxPageState']['libraries'])) {
+  if ($route_name && strpos($route_name, 'entity_browser') === 0 && isset($settings['ajaxPageState']['libraries'])) {
     $libraries = explode(',', $settings['ajaxPageState']['libraries']);
     // If we pretend EB's iframe library has not been previously loaded, it will
     // ALWAYS be fetched from the server, preventing (in a crappy, kludgey way)