testing: fix apiserver fixture panic if etcd is missing

Signed-off-by: Dr. Stefan Schimanski <[email protected]>

Author: sttts

pkg/internal/testing/controlplane/apiserver.go

@@ -421,6 +421,9 @@ func (s *APIServer) Stop() error {
 			return err
 		}
 	}
+	if s.Authn == nil {
+		return nil
+	}
 	return s.Authn.Stop()
 }