fix: avoid setup global dispatcher in advance

[himself65]

This relates to...

Rationale

Changes

lazy setup dispatcher so that lazyLoadUndici in node.js core module won't affect the globalThis

Features

Bug Fixes

Fixes: https://github.com/nodejs/node/issues/59012

Breaking Changes and Deprecations

Status

• [x] I have read and agreed to the Developer's Certificate of Origin
• [x] Tested
• [ ] Benchmarked (optional)
• [ ] Documented
• [ ] Review ready
• [ ] In review
• [ ] Merge ready

[mcollina]

CI doesn't seem happy

[himself65]

Yeah I see, trying to figure out

[himself65]

@mcollina updated the code

[KhafraDev]

Would it make more sense for undici to always overwrite the global dispatcher (if it's not from undici already)? Importing node:http might not cause issues anymore, but you'd still have these issues the second you used any of the undici-provided globals, right?