Kubelet service links error

[liggitt]

What type of PR is this?
/kind bug

What this PR does / why we need it:

• reverts kubelet-side defaulting added in bug: fix segfault when EnableServiceLinks is nil #73413
• returns an error if a nil enableServiceLinks pod spec value is encountered by the kubelet, rather than a panic

xref #71749

Does this PR introduce a user-facing change?:

Fixes panic if a kubelet is run against an older kube-apiserver

/sig node
/cc @dims @tallclair @joejulian

[k8s-ci-robot]

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In response to this:

What type of PR is this?
/kind bug

What this PR does / why we need it:

• reverts kubelet-side defaulting added in bug: fix segfault when EnableServiceLinks is nil #73413
• returns an error if a nil enableServiceLinks pod spec value is encountered by the kubelet, rather than a panic

Does this PR introduce a user-facing change?:

Fixes panic if a kubelet is run against an older kube-apiserver

/sig node
/cc @dims @tallclair @joejulian

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: liggitt

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[liggitt]

ping @dims / @tallclair

[dims]

/lgtm

Thanks for taking care of this @liggitt. Do we have any CI jobs that test this scenario? (curious)

[liggitt]

Do we have any CI jobs that test this scenario? (curious)

we don't have CI jobs that set up unsupported configurations that that I know of