refactor(cluster-autoscaler): move negative increase check earlier in executeScaleUp

[kincoy]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

This PR moves the defensive check for negative increase (NewSize < CurrentSize) earlier in the executeScaleUp function.

Previously, this check was performed after attempting to call increaseSize, which could lead to unnecessary cloud provider calls with invalid input. This change makes the validation occur before any cloud interaction, adhering to fail-fast principles.

The observability logic is preserved:

• Emits a warning event (FailedToScaleUpGroup)
• Records the failure via scaleStateNotifier
• Returns an InternalError with contextual information

Which issue(s) this PR fixes:

Fixes # (not applicable)

Special notes for your reviewer:

• This is a structural improvement; no change in behavior unless a negative scale-up delta is erroneously generated.
• Improves fast-fail behavior for invalid scale-up requests and avoids unnecessary cloud provider API calls.

Does this PR introduce a user-facing change?

NONE

[k8s-ci-robot]

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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

Hi @kincoy. Thanks for your PR.

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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[kincoy]

Friendly ping @vadasambar @BigDarkClown — this PR has been idle for a while. Would appreciate a review when convenient 🙏