title: getCurrentUser() doesn't give null
body: <p>My Android Project is linked to a Firebase Project. From the app, I have created a new account. Then, from the Firebase console, I have deleted all the accounts present. Then I have restarted the app. I was expected to have null when calling <code>mAuth.getCurrentUser()</code> but it doesn't (here the logcat). Why?</p>
  
  <p><a href="https://i.stack.imgur.com/gVayH.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gVayH.jpg" alt="enter image description here"></a></p>
  
  <p><strong>MyActivity.java</strong></p>
  
  <pre><code>private FirebaseAuth mAuth = FirebaseAuth.getInstance();
  
  @Override
  public void onStart() {
      super.onStart();
      currentUser = mAuth.getCurrentUser();
      System.out.println(currentUser.getUid());
  }
  </code></pre>
  
  <p><strong>Logcat</strong></p>
  
  <pre><code>11-03 14:48:49.250 25654-25654/com.example.ves.gennaio3 I/System.out: SESbqLQQyDX4qWEaKxBMBukVLrI2
  </code></pre>