Move `k8s` ephemeral test cluster to AKS instances with NVIDIA T4

[0x2b3bfa0]

(Continuation of #533) Once the quota increase request is approved, we should use Standard_NC4as_T4_v3 instead of Standard_NC6 to run the tests:

terraform-provider-iterative/.github/workflows/smoke.yml

Line 100 in 765225c

--node-vm-size=Standard_NC6 \