add some error handling for 404 responses to prevent crashes in get_image_refs.py

What does this MR do?

This MR add simple error handling. Specifically, it adds a try-except block to catch ApiException errors and handle the case where the pod is not found (404 error)

Why?

The script lists pods with client.CoreV1Api.list_pod_for_all_namespaces(), then retrieves pod details with client.CoreV1Api.read_namespaced_pod(pod_name,pod_namespace). Occasionally, the script crashes because the pod is not found.