Indicate the auth token type generated from the Diglogflow service
agent <https://cloud.google.com/iam/docs/service-agents#dialogflow-service-agent>__.
Values:
SERVICE_AGENT_AUTH_UNSPECIFIED (0):
Service agent auth type unspecified. Default to ID_TOKEN.
NONE (1):
No token used.
ID_TOKEN (2):
Use ID
token <https://cloud.google.com/docs/authentication/token-types#id>
generated from service agent. This can be used to access
Cloud Function and Cloud Run after you grant Invoker role to
service-<PROJECT-NUMBER>@gcp-sa-dialogflow.iam.gserviceaccount.com.
ACCESS_TOKEN (3):
Use access
token <https://cloud.google.com/docs/authentication/token-types#access>
generated from service agent. This can be used to access
other Google Cloud APIs after you grant required roles to
service-<PROJECT-NUMBER>@gcp-sa-dialogflow.iam.gserviceaccount.com.