Typings for Send accept a Promise but the function doesn't await it

## Environment information

**Version**: 5.0.1 (latest)
**Platform**: Windows 10 (x86_64)
**Node.js version**: 22.14.0
**TypeScript version**: 5.5.4

## What steps will reproduce the bug?

```ts
const getData = async (): Promise> => {
return { hello: "world" };
};

router.get("/test", (_req, res) => {
res.json(getData());
});
```

This compiles successfully but the response will be `{}`.

I expected either a compiler error or for the response to be `{"hello":"world"}`.