This sets the Service Account that should be used by node VMs created by
node auto-provisioning. This should cause the auto-provisioned nodes to
have the same permissions as the nodes that are manually provisioned.

The defaults I included come from the scopes I observed in a cluster I
stood up when no scopes were specified. I am assuming these are GKE
defaults. This does not match the default scopes for normal node pools
in this Terraform module, so it may not be the correct choice.

The API will not reject the defaults, but it also does not save them
when auto-provisioning is disabled. Which means your plan will
continually attempt to update the attributes, succeed, and then still
think they need to be updated.

I don't expect this to fix the tests, there is still the issue of the
serviceAccount.