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

app/chips-autocomplete-example.ts の StackBlitz reproduction から始め、Angular Material chips autocomplete example および Issue 14195 と比較します。FormControl を mat-chip-list に移動して required を追加することで失敗を再現し、その後 MatChipList と autocomplete の相互作用を追跡します。autocomplete がユーザーのテキストから結果をフィルタリングし、required control が引き続きサポートされれば完了です。

索引モデルが issue の本文から書いたものです。