identity_fn.AuthBlockingEvent is still missing auth_type and resource #316

Summary

#231 added event_type, email_type, and sms_type to identity_fn.AuthBlockingEvent (thanks!). Two properties from the blocking functions doc are still missing, so code written from the doc fails on Python:

Repro

from firebase_functions import identity_fn

@identity_fn.before_user_signed_in()
def handle(event: identity_fn.AuthBlockingEvent):
    event.auth_type  # AttributeError
    event.resource   # AttributeError

Checked against the AuthBlockingEvent dataclass on main (identity_fn.py) and in 0.6.0.

Where the values come from

The Node SDK derives both from the blocking token rather than reading dedicated claims, so Python can do the same. From parseAuthEventContext:

• authType is "USER" when the token has a user_record, otherwise "UNAUTHENTICATED".
• resource.service is identitytoolkit.googleapis.com, and resource.name is projects/<project-id>/tenants/<tenant_id> when the token has a tenant_id, otherwise projects/<project-id>.

Context

First reported in firebase/functions-samples#1129 and in #224, which #231 partly addressed. I'm closing the samples issue in favor of this one, since the fix belongs in the SDK. Until then, the tenant is available as event.data.tenant_id.