VPA: Fix regression where the case of Kind is inconsistant

[adrianmoisey]

Relates to #6924

Previously the case of the Kind in the targetRef didn't matter. Not it seems to matter for the admission-controller.

This change attempts to copy what the HPA does. https://github.com/kubernetes/kubernetes/blob/v1.30.0/pkg/controller/podautoscaler/horizontal.go#L1321-L1325

What type of PR is this?

/kind bug
/kind regression

What this PR does / why we need it:

This PR allows users to specify a kind in the targetRef and all 3 VPA components will still continue to work.
Prior to this change the admission-controller would ignore the new Pods if the case of the Kind was incorrect.

Which issue(s) this PR fixes:

Fixes # #6924

Special notes for your reviewer:

I'm not sure if this solution is the right way to go, but I copied the HPA as best I could, in order to maintain consistent behaviour between the VPA and HPA.
Another solution could be to change this line:

autoscaler/vertical-pod-autoscaler/pkg/utils/vpa/api.go

Line 167 in 131d12b

if vpaWithSelector.Vpa.Spec.TargetRef.Kind != parentController.Kind ||

It could do a strings.ToLower() before comparison.

Does this PR introduce a user-facing change?

Fix regression of how case was handled in the targetRef

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

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I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[adrianmoisey]

/area vertical-pod-autoscaler

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: adrianmoisey
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[k8s-ci-robot]

PR needs rebase.

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[adrianmoisey]

I don't think this is the right approach. Going to close this and see if I can get conversation going on the issue.