docs: Update documentation for auth/user-not-found exception to reflect email enumeration protection (#12964)

* Update documentation for auth/user-not-found exception to reflect email enumeration protection

* Update packages/firebase_auth/firebase_auth/lib/src/firebase_auth.dart

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Co-authored-by: Guillaume Bernos <guillaume.bernos@gmail.com>

Author: xemexpress

packages/firebase_auth/firebase_auth/lib/src/firebase_auth.dart

@@ -318,7 +318,7 @@ class FirebaseAuth extends FirebasePluginPlatform {
   /// - **auth/unauthorized-continue-uri**\
   ///   The domain of the continue URL is not whitelisted. Whitelist the domain in the Firebase console.
   /// - **auth/user-not-found**\
-  ///   Thrown if there is no user corresponding to the email address.
+  ///   Thrown if there is no user corresponding to the email address. Note: This exception is no longer thrown when enabling email enumeration protection.
   Future<void> sendPasswordResetEmail({
     required String email,
     ActionCodeSettings? actionCodeSettings,