Issue #3063339: Rename 'local_service' plugin to 'local_server'

Continues work of 5f321832.

src/Form/FillPdfSettingsForm.php

@@ -282,7 +282,7 @@ class FillPdfSettingsForm extends ConfigFormBase {
       '#title' => $this->t('Configure FillPdf LocalServer endpoint (address)'),
       '#default_value' => $config->get('local_service_endpoint'),
       '#description' => $this->t("Enter the network address of your FillPDF LocalServer installation. If you are running the Docker container on port 8085 locally, then the address is <em>http://127.0.0.1:8085</em>."),
-      '#group' => 'local_service',
+      '#group' => 'local_server',
     ];
 
     $form['pdftk'] = [