Update index.mdx (#30551)

Author: dinasaur404

src/content/docs/artifacts/index.mdx

@@ -23,7 +23,7 @@ Versioned storage that speaks Git.
 
 :::note
 
-Artifacts is in beta. Refer to [How Artifacts works](/artifacts/concepts/how-artifacts-works/) for the architecture overview.
+Artifacts is currently in closed beta. To request access, fill out [this form](https://forms.gle/DwBoPRa3CWQ8ajFp7).
 
 :::