Drop error condition from AKS node public IP prefix e2e test

[nojnhuh]

What type of PR is this?
/kind failing-test

What this PR does / why we need it:

This PR updates the public IP prefix AKS e2e test to drop triggering the PublicIpPrefixOutOfIpAddressesForVMScaleSet error condition from the test. Until earlier this week, scaling a node pool in that state would converge to a successful state. Now AKS fails to scale the node pool, reporting that the backing VMSS doesn't exist.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes https://storage.googleapis.com/k8s-triage/index.html?date=2025-08-22&pr=1&text=aks_public_ip_prefix

Special notes for your reviewer:

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• cherry-pick candidate

Release note:

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[nojnhuh]

/test pull-cluster-api-provider-azure-e2e-aks

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.94%. Comparing base (4ad8f96) to head (fe06842).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5833   +/-   ##
=======================================
  Coverage   46.94%   46.94%           
=======================================
  Files         279      279           
  Lines       29687    29687           
=======================================
  Hits        13936    13936           
  Misses      14938    14938           
  Partials      813      813           

☔ View full report in Codecov by Sentry.
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[nojnhuh]

#5690

/test pull-cluster-api-provider-azure-e2e-aks

[nojnhuh]

Looking for one more set of artifacts:

/test pull-cluster-api-provider-azure-e2e-aks

[nojnhuh]

AFAICT, this is a change in behavior on the AKS side. Attempting to scale a node pool currently in PublicIpPrefixOutOfIpAddressesForVMScaleSet will fail because the backing VMSS doesn't exist and AKS doesn't seem to try to create it. I'm following up with AKS to see if this is a bug, but in the meantime I've updated this PR to drop triggering that error condition from the test.

/retitle Drop error condition from AKS node public IP prefix e2e test
/release-note-none

[nojnhuh]

/kind failing-test

[nojnhuh]

Also failing on release branches:

/cherry-pick release-1.20
/cherry-pick release-1.21

[k8s-infra-cherrypick-robot]

@nojnhuh: once the present PR merges, I will cherry-pick it on top of release-1.20, release-1.21 in new PRs and assign them to you.

In response to this:

Also failing on release branches:

/cherry-pick release-1.20
/cherry-pick release-1.21

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.

[mboersma]

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: dff178a33b1f51dde12e618855aee0d0a5f6368a

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mboersma

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Needs approval from an approver in each of these files:

• OWNERS [mboersma]

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[k8s-infra-cherrypick-robot]

@nojnhuh: new pull request created: #5836

In response to this:

Also failing on release branches:

/cherry-pick release-1.20
/cherry-pick release-1.21

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.

[k8s-infra-cherrypick-robot]

@nojnhuh: new pull request created: #5837

In response to this:

Also failing on release branches:

/cherry-pick release-1.20
/cherry-pick release-1.21

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.