fix(ext/node): refactor http.ServerResponse into function class (#26210)

While testing, I found out that light-my-request relies on
`ServerResponse.connection`, which is deprecated, so I added that and
`socket`, the non deprecated property.

It also relies on an undocumented `_header` property, apparently for
[raw header
processing](https://github.com/fastify/light-my-request/blob/v6.1.0/lib/response.js#L180-L186).
I added it as an empty string, feel free to provide other approaches.

Fixes #19901

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>