chore: mark release mgmt new in unleash as beta (#9540)

Author: daveleek

frontend/src/component/layout/MainLayout/NavigationSidebar/NewInUnleash/NewInUnleash.tsx

@@ -170,6 +170,7 @@ export const NewInUnleash = ({
             preview: <ReleaseManagementPreview />,
             onCheckItOut: () => navigate('/release-management'),
             show: isEnterprise() && releasePlansEnabled,
+            beta: true,
             longDescription: (
                 <>
                     <p>