feat: enable proxy handling for native fetch and connectrpc calls

[AndreasZeissner]

Motivation and Context

Setting the proxy relies on undici for now undici does not respect the HTTP(S)_PROXY vars, it's planned to build it in from v23 on by default:

nodejs/node#43187 (comment)

My current plan is to add support for the HTTP_PROXY env variable
behind a flag in v22 (and possibly v20), then unflag in v23.

Using global dispatcher is the current way to go for native fetch,
therefore undici needs to be added.

For connectrpc the agent will be passed down the chain:

      /**
       * Options passed to the request() call of the Node.js built-in
       * http or https module.
       */
      nodeOptions?:
        | Omit<http.RequestOptions, "signal">
        | Omit<https.RequestOptions, "signal">;

Depending on the proxy, setting: export NODE_TLS_REJECT_UNAUTHORIZED=0 might be needed (e.g. calling the wgc npm "update" command)

TODO

• Tests or benchmark included
• Documentation is changed or added on https://app.gitbook.com/
• PR title must follow conventional-commit-standard

[Aenimus]

Some minor comments but LGTM