[Question] Assert in auth.cc line 119 when trying to create Auth

### [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-build SDK
* Firebase C++ SDK version: 12.1.0
* Main Firebase Components in concern: Auth (Auth, Database, etc.)
* Other Firebase Components in use: App,Firestore,Storage (Auth, Database, etc.)
* Platform you are using the C++ SDK on: Windows (Mac, Windows, or Linux)
* Platform you are targeting: iOS, Android (iOS, Android, and/or desktop)

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

I was not able to reproduce the issue on test-app where auth example works properly on desktop.

Issue occurs only on Desktop when using c++ wrapper on Windows (Android and iOS works fine)

I'm following general FirebaseApp creation:

`m_App = firebase::App::Create();`

later on when i try to get Auth by calling this code: (from the same thread)

```
firebase::App* app = FirebaseApp::Get();
if (!app)
return nullptr;

firebase::auth::Auth* auth = firebase::auth::Auth::GetAuth(app);
if (!auth)
return nullptr;

return auth;
```

I'm getting hard crash with assert from [auth.cc line 119](https://github.com/firebase/firebase-cpp-sdk/blob/main/auth/src/auth.cc#L119)

If I try to create auth immediately after creating app i will get a proper object but then calling eg.:

`firebase::Future result = auth->SignInAnonymously();`

Result in exact same assert.

Can you please assist what may be the cause? Is there some kind of releasing object under the hood?


auth/src/auth.cc の119行目から開始し、報告された Windows デスクトップフローを test-app にある動作する auth の例と比較します。同じスレッドで App::Create、Auth::GetAuth、SignInAnonymously を使用してシーケンスを再現します。Windows デスクトップの場合の assertion の原因を特定し、検証済みの解決策を文書化または実装できれば完了です。

索引モデルが issue の本文から書いたものです。