Seems like K8sClient wasn't raising K8sResourceNotFound exception on 404
from all the methods, e.g. patch. This commit makes sure that is no
longer the case and any 404 results in K8sResourceNotFound exception.
Change-Id: I23b947ef5f8c56429b5c69b73489fec19c44bd7e
Closes-Bug: 1865893