fix: [UIE-9841] - Hide dual stack option if no IPv6 prefixes available in create VPC flow

[grevanak-akamai]

Description 📝

As part of this PR, if the available VPC IPv6 prefix length for a DC is 0, then dual-stack option should not be shown under IP stack in create VPC flow.

Changes 🔄

• If availableRegionIPv6PrefixLengths > 0, only then show IPv4 + IPv6 (Dual Stack) option in create VPC screen.
• Make necessary changes to enable Create VPC flow in MSW setup with legacy MSW handlers enabled.
• Clean up unused VPC IPv6 Large Prefixes tag.

Scope 🚢

Upon production release, changes in this PR will be visible to:

• All customers
• Some customers (e.g. in Beta or Limited Availability)
• No customers / Not applicable

Target release date 🗓️

NA

Preview 📷

Before	After

How to test 🧪

Prerequisites

• Add new-dc-testing-alpha tag in prod account.
• In local, switch to prod environment.

Reproduction steps

• Go to https://cloud.linode.com/vpcs/create and select "us-iad-2" region.
• See that "Dual stack" option is visible under IP stack and submission of create form with dual stack option selected fails with related error.

Verification steps

• In local with prod environment setup, go to /vpcs/create and select "us-iad-2" region
• See that "Dual stack" option is not visible under IP stack as the DC doesn't supports multiple IPv6 prefixes.

Author Checklists

As an Author, to speed up the review process, I considered 🤔

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➕ Adding a changeset
🧪 Providing/improving test coverage
🔐 Removing all sensitive information from the code and PR description
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👣 Providing comprehensive reproduction steps
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• I have read and considered all applicable items listed above.

As an Author, before moving this PR from Draft to Open, I confirmed ✅

• All tests and CI checks are passing
• TypeScript compilation succeeded without errors
• Code passes all linting rules

[dwiley-akamai]

The ticket says, "If the available VPC IPv6 prefix lengths for a DC is empty, then dual-stack should not be shown," but this PR makes it not shown if there are zero or one prefix lengths. What's correct here? With the current logic it seems like Dual Stack won't be available for any region at this moment.

[grevanak-akamai]

The ticket says, "If the available VPC IPv6 prefix lengths for a DC is empty, then dual-stack should not be shown," but this PR makes it not shown if there are zero or one prefix lengths. What's correct here? With the current logic it seems like Dual Stack won't be available for any region at this moment.

Initially I thought we have to hide this even if only /52 prefix is available as per this condition. But I see that prefix will be defaulted to /52 even if prefixes are not shown when its length is 1. So updated the condition to show dual-stack option if there are any prefixes available.

[linode-gh-bot]

Cloud Manager UI test results

🔺 1 failing test on test run #3 ↗︎

❌ Failing	✅ Passing	↪️ Skipped	🕐 Duration
1 Failing	869 Passing	11 Skipped	42m 39s

Details

Failing Tests
	Spec	Test
❌	clone-linode.spec.ts	Cloud Manager Cypress Tests→clone linode » can clone a Linode from Linode details page

Troubleshooting

Use this command to re-run the failing tests:

pnpm cy:run -s "cypress/e2e/core/linodes/clone-linode.spec.ts"