title: Disabling auth/user-not-found functionality
body: <p>I have a React application with email &amp; password sign in method available (implemented with firebase). In the log in form, if you enter incorrect email, you will get <a href="https://firebase.google.com/docs/reference/js/firebase.auth.Auth#error-codes" rel="nofollow noreferrer">auth/user-not-found</a> error as expected.</p>
  <p>What are my options to disable this kind of behaviour? To me it seems to be a security risk where malicious user could query email addresses and see if the user exists on my platform or not.</p>