I have [JWT authentication](https://github.com/lexik/LexikJWTAuthenticationBundle) in Symfony app. 
`security.yaml`

```
security:
    encoders:
        App\Entity\User:
            algorithm: auto

    providers:
        app_user_provider:
            entity:
                class: App\Entity\User
                property: email

    firewalls:
        registration:
            pattern: account.register
            anonymous: true

        verification:
            pattern: account.verify
            anonymous: true

        login:
            pattern: account.login
            stateless: true
            anonymous: true
            json_login:
                check_path: account.login
                success_handler: lexik_jwt_authentication.handler.authentication_success
                failure_handler: lexik_jwt_authentication.handler.authentication_failure

        api:
            pattern: ^/api
            stateless: true
            provider: app_user_provider
            guard:
                authenticators:
                    - lexik_jwt_authentication.jwt_token_authenticator

```

I want to login users only with verified email. Now after registration, email is not verified yet, but user is already can login. I want to prevent it while `verified_at` is null in User entity.
How can I do this?