Submit handler for search_embedded_form_form().
function search_embedded_form_form_submit($form, &$form_state) {
$config = config('search_embedded_form.settings');
$submit_count = (int) $config
->get('submitted');
$config
->set('submitted', $submit_count + 1)
->save();
drupal_set_message(t('Test form was submitted'));
}