Example react-user-management: Unsubscribe onAuthStateChange listener. (#27799)

Example react-user-management:
Unsubscribe the sb.auth.onAuthStateChange listener on component cleanup.

examples/user-management/react-user-management/src/App.jsx

@@ -12,9 +12,11 @@ function App() {
       setSession(session)
     })
 
-    supabase.auth.onAuthStateChange((_event, session) => {
+    const { data } = supabase.auth.onAuthStateChange((_event, session) => {
       setSession(session)
     })
+
+    return () => data.subscription.unsubscribe();
   }, [])
 
   return (