Add Enterprise-only note

Author: hannes-cf

src/content/changelog/dns/2025-06-16-internal-dns-beta-ui.mdx

@@ -22,4 +22,8 @@ Participating beta testers can now fully configure Internal DNS directly in the
 
 ![Internal DNS UI](~/assets/images/changelog/dns/internal-dns-beta-ui.png)
 
+:::note
+The Internal DNS beta is currently only available to Enterprise customers.
+:::
+
 To learn more and get started, refer to the [Internal DNS documentation](/dns/internal-dns/).