FR: Enable anonymous authentication when creating and updating a tenant

[sonatard]

It can solve to add enableAnonymousUser param to CreateTenant and UpdateTenant.

API

CreateTenant and UpdateTennant request body have Tenant.

https://cloud.google.com/identity-platform/docs/reference/rest/v2/projects.tenants/create
https://cloud.google.com/identity-platform/docs/reference/rest/v2/projects.tenants/patch

Tenant type has enableAnonymousUser.

https://cloud.google.com/identity-platform/docs/reference/rest/v2/projects.tenants#Tenant

[bojeil-google]

We are already working on this. @rsgowman is leading that work in all the major languages:

firebase/firebase-admin-node#802