[Route] Add route for MDM enrollment guide (#48658)

<!-- Add the related story/sub-task/bug number, like Resolves #123, or
remove if NA -->
**Related issue:** Resolves #41787 

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Added a new redirect for the “Learn more about MDM enrollment” page,
sending visitors to the Windows MDM setup guide’s manual enrollment
section.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

website/config/routes.js

@@ -1364,6 +1364,7 @@ module.exports.routes = {
   'GET /learn-more-about/self-service-categories': '/guides/software-self-service#manage-self-service-categories',
   'GET /learn-more-about/linux-wipe': '/guides/lock-wipe-hosts#linux-wipe-behavior',
   'GET /learn-more-about/configuration-profile-assets': '/articles/custom-os-settings#apple-declarations-ddm',
+  'GET /learn-more-about/mdm-enrollment': '/guides/windows-mdm-setup#manual-enrollment',
 
   // Sitemap
   // =============================================================================================================