Merge branch '213282-handle-invalid-routes' into 'master'

Handle invalid routes in Static Site Editor

See merge request gitlab-org/gitlab!31648

app/assets/javascripts/static_site_editor/router/routes.js

@@ -14,4 +14,8 @@ export default [
     path: '/success',
     component: Success,
   },
+  {
+    path: '*',
+    redirect: HOME_ROUTE,
+  },
 ];