fix(eio-client/types): avoid MapIterator in generated typings

[lazerg]

The kind of change this PR does introduce

• a bug fix
• a new feature
• an update to the documentation
• a code change that improves performance
• other

Current behavior

The cookies getter in globals.node.ts has no return type, so TypeScript 6 infers it from Map#entries() and writes MapIterator<[string, Cookie]> into globals.node.d.ts. MapIterator only exists in the lib files of TypeScript 5.6 and later, so projects on an older compiler (like the Angular 17 client in the basic CRUD example, which uses TypeScript 5.2) fail with TS2552: Cannot find name 'MapIterator' unless skipLibCheck is on.

New behavior

The getter is annotated as IterableIterator<[string, Cookie]>, which every TypeScript version understands. I checked that the regenerated .d.ts compiles cleanly with TypeScript 5.0 and 5.2.

Other information (e.g. related issues)

Fixes #5567