Expose information about the current range to the datepicker actions

#### What are you trying to do?

I am trying to disable the apply button inside mat-date-range-picker-actions until a range is selected

#### What troubleshooting steps have you tried?

tried to see if any events fire on day selection so I can determine if the range is correct

#### Reproduction

https://stackblitz.com/edit/angular-date-range-picker-actions?file=src/app/date-range-picker-forms-example.html
Well, here is a start point. I could not find a way to disable the Apply button until both dates are selected.
Reson is the form data is not updated until Apply is clicked and I could not find any events that trigger on day selection. There are some for year and month but not day.

#### Environment

- Angular: 12
- CDK/Material: latest
- Browser(s): N/A
- Operating System (e.g. Windows, macOS, Ubuntu): N/A

Inizia dalla riproduzione StackBlitz collegata e traccia il modo in cui mat-date-range-picker-actions riceve lo stato e in cui viene esposta la selezione dei giorni. Il lavoro è completato quando le actions possono determinare se entrambe le date dell’intervallo corrente sono selezionate, consentendo al pulsante Apply di rimanere disabilitato finché l’intervallo non è completo.

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