Update same_page_preview.module

Closes #3348897

same_page_preview.module

@@ -19,7 +19,14 @@ function same_page_preview_preprocess_html(&$variables) {
     $route_name = \Drupal::routeMatch()->getRouteName();
     if ($route_name === 'entity.node.preview') {
       unset($variables['page_top']['toolbar']);
-      // TODO - Needs additional cleanup to remove toolbar related classes on body.
+      // Additional cleanup to remove toolbar related classes on body.
+      if (isset($variables['attributes']['class']) && is_array($variables['attributes']['class']) && $variables['attributes']['class']) {
+        foreach ($variables['attributes']['class'] as $index => $class) {
+          if (strpos($class, 'toolbar') !== FALSE) {
+            unset($variables['attributes']['class'][$index]);
+          }
+        }
+      }
       // Remove contextual links.
       $variables["page"]["#attached"]["library"] = array_values(array_diff($variables["page"]["#attached"]["library"], ['contextual/drupal.contextual-links']));
     }