This PR changes the HA check that verifies that the `config.linkerd.io/admission-webhooks=disabled` is present on kube-system to be enabled only when the failure policy for the proxy injector webhook is set to `Fail`. This allows users to skip this check in cases when the label is removed because the namespace is managed by the cloud provider like in the case described in #4754Fix#4754
Signed-off-by: Zahari Dichev <zaharidichev@gmail.com>