[Auth Guard - BUG] canActivate auth guard causes blank screen after cache clear with multiple tabs opens.

If using the canActivate auth guard (with spread syntax), If you have more than 1 tab open of the same app, and then you clear the cache by using the browser in one of the tabs, and try to refresh, it causes a blank screen, which resolves after you close the other open tab.

steps to reproduce:

versions:
"@angular/common": "^20.3.0",
"@angular/compiler": "^20.3.0",
"@angular/core": "^20.3.0",
"@angular/fire": "^20.0.1",
"@angular/forms": "^20.3.0",
"@angular/platform-browser": "^20.3.0",
"@angular/router": "^20.3.0",
"rxjs": "~7.8.0",
"tslib": "^2.3.0",
"zone.js": "~0.15.0"

steps to reproduce:
1. Create new project
2. install angular fire
3. setup authentication and firebase project
4. utilize the ...canActivate auth guard like below.
5. open two tabs of the same page.
6. in one of them, clear the cache (by using the button close to the url in chrome for ex)
7. refresh
8. blank screen.
9. verify that if you close the second tab, then the first one loads correctly.

```TS
const redirectTeste1 = () => redirectLoggedInTo('test2');
const redirectTeste2 = () => redirectUnauthorizedTo('teste1');

export const routes: Routes = [
{ path: '', redirectTo: 'teste1', pathMatch: 'full' },

{
path: 'teste1',
component: Test1,
...canActivate(redirectTeste1),
},

{
path: 'teste2',
component: Test2,
...canActivate(redirectTeste2),
},
];
```

lmk if this is somehow a user error, but with such a barebones configuration I think is a legitimate bug.

Inizia con la configurazione minima dell’autenticazione AngularFire descritta nell’issue, usando il guard canActivate con redirectLoggedInTo e redirectUnauthorizedTo. Riproduci il comportamento con due schede, svuota la cache in una di esse e aggiornala. È completato quando la scheda aggiornata viene caricata normalmente invece di mostrare una schermata vuota mentre l’altra scheda rimane aperta.

Scritto dal modello di indicizzazione a partire dal testo della issue.