setPersistence(Auth.Persistence.LOCAL) Promise hangs, onIdTokenChanged/onAuthStateChanged never fire (mainly iOS, Firebase JS 8.10.1)

### Operating System

Primarily observed on iOS devices in production (Ionic 5 + Capacitor 6 + React 17)

### Environment (if applicable)

Mobile: iOS (sporadic, seen in logs and user reports) and Framework: Ionic 5, Capacitor 6, React 17

### Firebase SDK Version

8.10.1

### Firebase SDK Product(s)

Auth

### Project Tooling

Ionic 5, Capacitor 6, React 17

### Detailed Problem Description

Some users mainly on iOS as currently seen in our logs get stuck on the loading screen when opening the app.
• The ‎`onIdTokenChanged` and ‎`onAuthStateChanged` callbacks never fire (no logs output).
• Wrapping ‎`setPersistence(Auth.Persistence.LOCAL)` with ‎`.then`/‎`.catch` logs shows neither handler runs—the Promise remains pending.
• ‎`firebase.auth().currentUser` is logged right before the listener is attached, confirming the code path is reached.
• This appears related to IndexedDB, which ‎`setPersistence(LOCAL)` relies on. If IndexedDB open hangs (possibly more likely on iOS), the Promise never resolves and authentication events do not fire.

Example code:this.firebaseAuth
.setPersistence(Auth.Persistence.LOCAL)
.then(() => console.log('[Auth] persistence set')) // never prints
.catch(err => console.error('[Auth] persistence error', err)); // never prints

Reproducibility:
• Sporadic in production, mainly on iOS; not yet reproduced internally

### Steps and code to reproduce issue

1. Use Firebase JS SDK 8.10.1 in an Ionic 5 + Capacitor 6 + React 17 app.
2. Call ‎`setPersistence(Auth.Persistence.LOCAL)` before setting up auth listeners.
3. For some iOS users, the Promise never resolves or rejects, and callbacks for ‎`onIdTokenChanged`/‎`onAuthStateChanged` never fire.
4. No error is logged, and the app remains stuck on the loading screen.