test: don't check logs if kubectl is nil
test: don't check logs if kubectl is nil

Added a nil check in log check function since it can be run after test
failed due to kubectl failing to set up, resulting in a panic.

Signed-off-by: Maciej Kwiek <33c1fdf481c8e628d4c6db7ea8dc77f49f2fa5d7@isovalent.com>

michi-covalent/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,cilium/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,tklauser/cilium