Remove closed beta message

Author: cmanallen

platform-includes/feature-flags/prerelease-alert/_default.mdx

@@ -1,5 +1,5 @@
 <Alert level="info" title="Currently in Beta">
 
-Feature flag change tracking and feature flag evaluation tracking is currently in closed beta. If you'd like to be added to the beta, please fill out [this form](https://forms.gle/EeNwTepvVwt7poAJ8).
+Feature flag change tracking and feature flag evaluation tracking is currently in open beta.
 
 </Alert>