feat(MatChipList): add better out-of-the-box support for FormControls

#### Reproduction

Use StackBlitz to reproduce your issue: https://stackblitz.com/edit/chips-autocomplete-required-failure?file=app/chips-autocomplete-example.ts

Steps to reproduce:
1. Fork the mat-chips autocomplete example from the Angular documentation
2. Move the form control to the mat-chip-list and add required attribute
3. Try using the auto complete 💥

NOTE: Followed suggestion in the following issue to add the required field, but that example doesn't include autocomplete. With this the autocomplete breaks. https://github.com/angular/components/issues/14195

#### Expected Behavior

The autocomplete should filter results based on text entered.

#### Actual Behavior

The autocomplete does not filter the results based on the text input from the user.

#### Environment

- Angular: 8.2.14
- CDK/Material: 8.2.3
- Browser(s): Chrome 81.0.4044.138
- Operating System (macOS): Mojave 10.14.6

Inizia con la riproduzione StackBlitz in app/chips-autocomplete-example.ts e confrontala con l’Angular Material chips autocomplete example e l’Issue 14195. Riproduci il problema spostando il FormControl in mat-chip-list e aggiungendo required, quindi traccia l’interazione tra MatChipList e autocomplete. Il lavoro è completato quando autocomplete filtra i risultati in base al testo dell’utente mentre il controllo required continua a essere supportato.

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