Replace all the civi message templates with the on-disk version

ReplaceMessageTemplates.php

<?php

/**
 * IMPORTANT: Make a backup of the civicrm_msg_template table first.
 * Run with `cv php:script ReplaceMessageTemplates.php`
 *
 * While there's a link on the message templates admin page to revert a workflow
 * message template, what that does is replaces your current version with the
 * default FROM THE DATABASE.
 * That default is, in theory, the same as the latest version on disk in the
 * xml/templates/message_templates folder, but for various reasons over time
 * it may have gotten out of sync.
 * This unconditionally replaces both that default in the database and the
 * current version in the database with the latest file contents from on-disk.
 */
class ReplaceMessageTemplates extends \CRM_Upgrade_Incremental_MessageTemplates {
  /**
   * Override
   */
  public function getTemplatesToUpdate() {
    $templates = [];
    $dao = CRM_Core_DAO::executeQuery('SELECT workflow_name FROM civicrm_msg_template WHERE workflow_name IS NOT NULL GROUP BY workflow_name');
    while ($dao->fetch()) {
      $templates[] = ['name' => $dao->workflow_name, 'type' => 'subject'];
      $templates[] = ['name' => $dao->workflow_name, 'type' => 'text'];
      $templates[] = ['name' => $dao->workflow_name, 'type' => 'html'];
    }
    return $templates;
  }
}

(new ReplaceMessageTemplates('dontcare'))->updateTemplates();