RecaptchaVerifier example missing authExtern parameter

### Operating System

macOS

### Browser Version

Safari 16.5.2

### Firebase SDK Version

10.3.0

### Firebase SDK Product:

Auth

### Describe your project's tooling

index.html with source tag.

### Describe the problem

[Example](https://firebase.google.com/docs/reference/js/auth.md#example_8) of RecaptchaVerified doesn't use authExtern parameter of the [constructor](https://firebase.google.com/docs/reference/js/auth.recaptchaverifier.md#recaptchaverifierconstructor). This generates an error.

### Steps and code to reproduce issue

Already explained.