fix(controller): make managed namespaces more 'prune-proof' (cherry-pick #13999)#15488

jannfis merged 1 commit intorelease-2.8argoproj/argo-cd:release-2.8from

cherry-pick-dd25d3-release-2.8argoproj/argo-cd:cherry-pick-dd25d3-release-2.8Copy head branch name to clipboard