[7.2.0] Angular HMR: FirebaseError: Firestore has already been started and persistence can no longer be enabled

### Version info

**Angular:** 13.2

**Firebase:** 9.6

**AngularFire:** 7.2

### How to reproduce these conditions

**Steps to set up and reproduce**

- serve Angular project with `ng serve --hmr`
- make some change in the application

### Debug output

** Errors in the JavaScript console **

`FirebaseError: Firestore has already been started and persistence can no longer be enabled. You can only enable persistence before calling any other methods on a Firestore object.`

### Expected behavior

No errors.

### Actual behavior

Project fails to run with the above error.

Might be related to #2655

`ng serve --hmr` を使って Angular プロジェクトをサーブし、アプリケーションを変更して失敗を再現します。次に、AngularFire の Firestore 初期化と永続化のセットアップを追跡します。HMR の変更によって FirebaseError が発生しなくなれば、issue は完了です。

索引モデルが issue の本文から書いたものです。