Ensure mapping_id is pre-filled into the metadata-template

https: //github.com/civicrm/civicrm-core/pull/26108

Bug: T303986

Change-Id: I79f3265e838c9a5523fd3898b97ef82a9d4d95b8

drupal/sites/all/modules/civicrm/CRM/Import/Form/DataSource.php

@@ -220,6 +220,7 @@ public function setTemplateDefaults(): array {
       $mappingID = Mapping::get(FALSE)->addWhere('name', '=', $mappingName)->addSelect('id')->execute()->first()['id'];
       // Unset fields that should not be copied over.
       unset($userJob['id'], $userJob['name'], $userJob['created_date'], $userJob['is_template'], $userJob['queue_id'], $userJob['start_date'], $userJob['end_date']);
+      $userJob['metadata']['Template']['mapping_id'] = $mappingID;
       $userJob['metadata']['template_id'] = $templateID;
       $userJob['created_id'] = CRM_Core_Session::getLoggedInContactID();
       $userJob['expires_date'] = '+1 week';