feat: add a REST sample and test for AML AI

[irataxy]

Description

Fixes b: 355523386

Note: Before submitting a pull request, please open an issue for discussion if you are not associated with Google.

Checklist

• [X] I have followed guidelines from CONTRIBUTING.MD and Samples Style Guide
• [X] Tests pass: npm test (see Testing)
• [X] Lint pass: npm run lint (see Style)
• [X] These samples need a new API enabled in testing projects to pass (let us know which ones)
• [ ] These samples need a new/updated env vars in testing projects set to pass (let us know which ones)
• [X] This pull request is from a branch created directly off of GoogleCloudPlatform/nodejs-docs-samples. Not a fork.
• [X] This sample adds a new sample directory, and I updated the CODEOWNERS file with the codeowners for this sample
• [X] This sample adds a new sample directory, and I created GitHub Actions workflow for this sample
• [] This sample adds a new Product API, and I updated the Blunderbuss issue/PR auto-assigner with the codeowners for this sample
• [X] Please merge this PR for me once it is approved