feat: support optimizeEmptyRequests node option handling

[bjohansebas]

finalhandler is used as a callback in the router's handler when there’s no error handler or callback (https://github.com/expressjs/express/blob/2eb42059f33d9be6ead3bb813d05aa975283d592/lib/application.js#L154), and for some reason, the response wasn’t finishing. When I realized it, the on-finished callback was never triggered (

finalhandler/index.js

Line 291 in 62cc7e0

onFinished(req, write)

or

finalhandler/index.js

Line 282 in 62cc7e0

if (isFinished(req)) {

), which was the one used to mark the request as completed.

ref: https://openjs-foundation.slack.com/archives/C08QG8K2RTJ/p1757863264523329
ref: expressjs/express#6742