[FR] Support client option in create / update tenant

**Is your feature request related to a problem? Please describe.**
Currently the library does not support sending the [client](https://cloud.google.com/identity-platform/docs/reference/rest/v2/projects.tenants#ClientPermissionConfig) key in the createTenant/updateTenant methods.

**Describe the solution you'd like**
Support the client key as described in the documentation linked above.

**Describe alternatives you've considered**
I'm manually sending the request using fetch, but it bypasses all the validation that the normal methods provide, and is a pain to get the authentication headers.

**Additional context**
N/A