Issue #2537600 by DuaelFr: An empty path on search pages settings leads to an...

Issue #2537600 by DuaelFr: An empty path on search pages settings leads to an infinit redirection loop

core/modules/search/src/Form/SearchPageFormBase.php

@@ -112,6 +112,7 @@ public function form(array $form, FormStateInterface $form_state) {
       '#field_prefix' => 'search/',
       '#default_value' => $this->entity->getPath(),
       '#maxlength' => '255',
+      '#required' => TRUE,
     );
     $form['plugin'] = array(
       '#type' => 'value',