Merge pull request kubernetes#128340 from googs1025/automated-cherry-pick-of-#127834-upstream-release-1.31

Automated cherry pick of kubernetes#127834: fix(leaderelection): nil check in OnStoppedLeading func

Author: k8s-ci-robot

pkg/controlplane/controller/leaderelection/run_with_leaderelection.go

@@ -50,7 +50,9 @@ func RunWithLeaderElection(ctx context.Context, config *rest.Config, newRunnerFn
 			run(ctx, 1)
 		},
 		OnStoppedLeading: func() {
-			cancel()
+			if cancel != nil {
+				cancel()
+			}
 		},
 	}