User is not refreshed after applyActionCode

### [REQUIRED] Describe your environment

* Operating System version: OSX
* Browser version: Chorme 88.0.4324.182
* Firebase SDK version: 8.2.5
* Firebase Product: auth

#### Steps to reproduce:

It's possible to write custom email handlers https://firebase.google.com/docs/auth/custom-email-handler.

However after running firebaseApp.auth().applyActionCode(oobCode) firebaseApp.auth().currentUser is not refreshed automatically. Which means in email-verify case that firebaseApp.auth().currentUser seems to still have unverified email. It's also possible to call firebaseApp.auth().currentUser.reload() after but this does not cause onAuthChanged/onIdTokenChanged event handlers to be called.

Currently fixed by calling firebaseApp.auth().currentUser.getIdToken(true) in the end but I think this should happen automatically or added to documentation.
#### Relevant Code:

```javascript
// assume user is already loggedIn
await firebaseApp.auth().applyActionCode(oobCode);
await firebaseApp.auth().currentUser.getIdToken(true); // without this loggedin user is not refreshed
```