the flag is being removed after a long deprecation period:
kubernetes/kubernetes#91506

in kubeadm we are passing:
--insecure-port=0 in the api server static pod.

the flag became a no-op in 1.20:
kubernetes/kubernetes#95856

it will be removed in 1.24:
https://github.com/kubernetes/kubernetes/pull/95856/files#diff-3149c6ede53e3a658bbcf11f1456f2ac955ae49db5ab66ee9e13f883488349d3R151

kubeadm can remove it earleir

related to:
#2207

NOTE

this PR might do the change in kubeadm as well:
kubernetes/kubernetes#95522