feat(apigateway): dualstack custom domain REST API

[pedropedruzzi]

Issues

Resolves the missing domain name part of #33998. Note: the part for default REST API endpoints was done in PR #34114.

Reason for this change

Allow enabling dualstack on REST API custom domain endpoints.

Description of changes

• Defined a new EndpointConfiguration exclusive for DomainName, instead of using the existing interface of the RestApi class.
• Since there is already the endpointType prop in the domain name level, I decided to omit the types from EndpointConfiguration to avoid having two ways to set the same thing.
• I've considered the alternative design of having endpointIpAddressType directly in domain name (without endpoint configuration level). This is even cleaner but I thought it makes more sense to keep things in the same overall structure as API/CFN (e.g. to better cope with future field additions on the endpoint configuration). Let me know if you think this design is superior.

Describe any new or updated permissions being added

None.

Description of how you validated changes

Added unit and integration test cases. I hope to see integration tests run in CI.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[github-actions]

⚠️ The following issue reference(s) in your PR description are not valid issues:

• feat(apigateway): dualstack REST API #34114 (is a pull request, not an issue)

Please make sure your PR references an existing issue using the format Closes #123.

[aws-cdk-automation]

(This review is outdated)

✅ Updated pull request passes all PRLinter validations. Dismissing previous PRLinter review.