feat(dialog): Support async `MatDialogConfig.closePredicate`

### Feature Description

For a long time we wanted to be able to cancel dialog closure, in #14292. It was solved via a new option, `closePredicate`, in #14292. But that new option does not support async code. And so we cannot, for example, ask user for the confirmation to close the dialog (via a second dialog), nor do XHR to verify things on server-side.

This kind of use case was already mentioned by @teolag in https://github.com/angular/components/issues/14292#issuecomment-2828734239, but that specific part of the message was left unanswered. And @Nakira had to come up with a custom solution to solve this in https://github.com/angular/components/issues/14292#issuecomment-2907749489

### Use Case

I want the dialog closure to wait until I know whether it can be closed. Possibly via asking the user that he is OK to lose all the data he just input in the dialog, like so:

```ts
this.matDialog.open(MyDialogComponent, {
closePredicate: async () => await askUserIfReallySure(),
});
```

Inizia con il comportamento esistente di MatDialogConfig.closePredicate e il flusso di chiusura della finestra di dialogo; l’issue fornisce l’opzione pubblica e un esempio di utilizzo asincrono. Traccia la gestione del risultato del predicato, quindi verifica che la chiusura della finestra di dialogo attenda una conferma asincrona e continui a supportare l’annullamento.

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