acquia_search-3.0.1/modules/acquia_search_defaults/acquia_search_defaults.module

<?php

/**
 * @file
 * Provides the default settings for Acquia Search service.
 */

use Drupal\Core\Entity\EntityInterface;

/**
 * Implements hook_entity_operation_alter().
 *
 * Don't allow delete default server and index.
 */
function acquia_search_defaults_entity_operation_alter(array &$operations, EntityInterface $entity) {
  if (empty($operations['delete'])) {
    return;
  }

  $do_not_delete = [
    'acquia_search_server',
    'acquia_search_index',
  ];

  if (in_array($entity->id(), $do_not_delete, TRUE)) {
    unset($operations['delete']);
  }

}