Issue #3426100: Fix static call to instance method in fillpdf.install

fillpdf.install

@@ -29,7 +29,7 @@ function fillpdf_update_8101() {
     ->setDescription(t('This setting is used as the storage/download method for generated PDFs. The use of public files is more efficient, but does not provide any access control. Changing this setting will require you to migrate associated files and data yourself and is not recommended after you have uploaded a template.'))
     ->setDisplayOptions('form', [
       'type' => 'radios',
-      'options' => FillPdfAdminFormHelper::schemeOptions(),
+      'options' => \Drupal::service('fillpdf.admin_form_helper')->schemeOptions(),
     ]);
   $edum->installFieldStorageDefinition('scheme', 'fillpdf_form', 'fillpdf_form', $scheme_field);
 }