test: refine verify-helm-chart-index.sh

[andyzhangx]

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

What this PR does / why we need it:
test: refine verify-helm-chart-index.sh

Which issue(s) this PR fixes:

Fixes #

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Special notes for your reviewer:

Release note:

none 

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andyzhangx

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• OWNERS [andyzhangx]

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[Copilot]

Pull Request Overview

This PR refines the verify-helm-chart-index.sh script to improve URL validation logic by expanding the ignore mechanism. The changes enhance the script's ability to handle URLs containing "latest" and other dynamically determined ignore patterns.

• Enhanced URL ignore logic for "latest" URLs by capturing the filename for subsequent filtering
• Added conditional logic to ignore URLs containing a previously determined ignore filename

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[andyzhangx]

/cherrypick release-1.27

[andyzhangx]

/cherrypick release-1.26

[andyzhangx]

/cherrypick release-1.25

[k8s-infra-cherrypick-robot]

@andyzhangx: new pull request created: #2177

In response to this:

/cherrypick release-1.27

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]

@andyzhangx: new pull request created: #2178

In response to this:

/cherrypick release-1.26

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]

@andyzhangx: new pull request created: #2179

In response to this:

/cherrypick release-1.25

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.