ci: test: k8s: agent_image rootfs check

[stevenhorsman]

In the kubernetes agent_image test we currently have a check:

echo "Check the image was not pulled in the host"
	local pod_id=$(kubectl get pods -o jsonpath='{.items..metadata.name}')
	retrieve_sandbox_id
	rootfs=($(find /run/kata-containers/shared/sandboxes/${sandbox_id}/shared \
		-name rootfs))
	[ ${#rootfs[@]} -eq 1 ]

to ensure that the image hasn't been pulled onto the host. The reason that the check is for a single rootfs is that we found that the pause image was always pulled on the host, presumably due to it being needed to create the pod sandbox.

With the introduction of the nydus-snapshotter code we've found that on some systems (SE and TDX) it appears to be in a different location with nydus-snapshotter, so check for 1, or 0. See an issue at #5781 to track this.

We don't have time to understand this fully now, so we just want the tests to pass and check that we don't have both the pause and main pod container image pulled

[stevenhorsman]

Closed with #5791 merging