fix: undici incorrectly copies headers onto fetches

[codebytere]

Description of Change

Closes #41005.
Refs nodejs/node#50153
Refs nodejs/undici#2359

Fixes an issue where undici in migrating build scripts accidentally regressed constructor name exports.

This is fixed in Node.js v20.10.0 and beyond by nodejs/node#50274 but as that PR is very large, this cherry-picks out just the fix for the constructor issue by running the build script with the missing keepNames argument and copying the resulting undici-fetch.js output to deps/undici/undici.js, as Node.js themselves do in their update script

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Fixes an issue where Request objects did not correctly copy headers into fetches.

[ckerr]

oof, that's a big cherry-pick 🍒

[jkleinsc]

Patch fails to apply

[codebytere]

@jkleinsc i got some weird CRLF errors in console initially - i think it might be related. I'll check it out - it applied locally and i didn't make it too hackily so idk what else it could be 🤔

[release-clerk]

Release Notes Persisted

Fixes an issue where Request objects did not correctly copy headers into fetches.

[trop]

I have automatically backported this PR to "28-x-y", please check out #41103