[Question] Disable auto-login in Firebase?

### [READ] For Firebase Unity SDK question, please report to [Firebase Unity Sample](https://github.com/firebase/quickstart-unity/issues/new/choose)

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### [REQUIRED] Please fill in the following fields:

* Pre-built SDK from the [website](https://firebase.google.com/download/cpp) or open-source from this repo: **pre-built SDK**
* Firebase C++ SDK version: **12.7.0**
* Main Firebase Components in concern: **Auth** (Auth, Database, etc.)
* Other Firebase Components in use: _____ (Auth, Database, etc.)
* Platform you are using the C++ SDK on: **Ubuntu 24.04** (Mac, Windows, or Linux)
* Platform you are targeting: **Desktop** (iOS, Android, and/or desktop)

### [REQUIRED] Please describe the question here:

I want to disable auto-login, that is, I want to make that when the user opens my Desktop application `current_user()->is_valid()` evaluates to `false` (no currently active user).

At the moment the authentication state looks like to persist, I've tried avoiding this by signin-out as soon as I connect to the API:

```c++
m_firebase_app = firebase::App::Create(app_options);
m_firebase_auth = firebase::auth::Auth::GetAuth(m_firebase_app);
m_firebase_auth->SignOut();
m_firebase_auth->current_user().is_valid(); // Is still true with valid uid/email
```

But it does not work.

Another question: where is the authentication persisted on my local filesystem (which path)?

Commencez par les appels à firebase::App::Create, firebase::auth::Auth::GetAuth, SignOut() et current_user() présentés dans le rapport. Examinez l’implémentation desktop de Auth et son comportement de persistance afin de déterminer si la connexion automatique peut être désactivée et où les identifiants sont stockés ; le travail est terminé lorsque des réponses confirmées aux deux questions sont fournies.

Rédigé par le modèle d'indexation à partir du texte de l'issue.