Relax error on annotations read failure

Signed-off-by: apostasie <[email protected]>

pkg/cmd/container/kill.go

@@ -143,7 +143,10 @@ func cleanupNetwork(ctx context.Context, container containerd.Container, globalO
 		networksJSON := spec.Annotations[labels.Networks]
 		var networks []string
 		if err := json.Unmarshal([]byte(networksJSON), &networks); err != nil {
-			return err
+			log.G(ctx).WithError(err).Warnf("Unable to read network annotation: this container was probably not started with nerdctl." +
+				"No networking cleanup will be performed, which may likely result in a broken state for the other systems you used to manage these containers." +
+				"Mixing completely different stacks to manage containers lifecycle is not recommended.")
+			return nil
 		}
 		netType, err := nettype.Detect(networks)
 		if err != nil {