[DOCS] for sample: auth-blocking-functions | Cannot extract event_type

### [auth-blocking-functions](https://github.com/firebase/functions-samples/tree/main/Python/quickstarts/auth-blocking-functions)

Given the Google Documentations here to [Getting user and context information](https://firebase.google.com/docs/auth/extend-with-blocking-functions?gen=2nd#getting_user_and_context_information), some fields are not available on the `AuthBlockingEvent` dataclass.

For example I can extract the following:
```python
from firebase_admin import initialize_app
from firebase_functions import https_fn, identity_fn, options

initialize_app()

@identity_fn.before_user_signed_in()
def handle_user(
event: identity_fn.AuthBlockingEvent,
) -> identity_fn.BeforeSignInResponse | None:
email = event.data.email
uid = event.data.uid
event_id = event.event_id
```

However, the following does on exist on the even signature.
```python
from firebase_admin import initialize_app
from firebase_functions import https_fn, identity_fn, options

initialize_app()

@identity_fn.before_user_signed_in()
def handle_user(
event: identity_fn.AuthBlockingEvent,
) -> identity_fn.BeforeSignInResponse | None:
event_type = event.event_type
auth_type = event.auth_type
resource = event.resource
# etc
```