Remove legacy NodeAuditAnalyzer dependency on NPM audit legacy /quick API

**Is your feature request related to a problem? Please describe.**

The NodeAuditAnalyzer currently relies on the NPM v1 security audit API. This has had some recent stability problems, but as of 15 April 2026 it has started largely returning HTTP 410 errors with `This endpoint is being retired. Use the bulk advisory endpoint instead. See the following docs for more info: https://api-docs.npmjs.com/#tag/Audit`

At time of writing, there appears to be nothing official on GitHub/npm blog : https://github.blog/tag/npm/

**Describe the solution you'd like**

We'll have to evaluate whether we should use the bulk advisories endpoint, or whether we should be directly integrating at all anymore. https://api-docs.npmjs.com/#tag/Audit/operation/bulkAudit

I suspect we should just drop the code entirely though, and use `npm` CLI directly like the `pnpm` analyzer does.

**Additional context**

- PNPM upstream needs to migrate: #8421
- Yarn Audit Analyzer (in classic mode) would also need to migrate: #8423
- Yarn Audit Analyzer (in berry mode) seems OK as Yarn already uses the bulk API