Proxy not inferred as a promise when it's a nested inside a proxied object as a property value

If a situation arises where you need to pass a `proxy()`-ed object to another, the TS types lose track of what should be a Promise.

```ts
// worker
import { expose, proxy } from 'comlink';

const createProxyObject = () => {
const someOtherObject = { /*...*/ };

const newObj = {
someOtherObject: proxy(someOtherObject),
getSomeOtherObject: () => proxy(someOtherObject),
};

return proxy(newObj);
};

expose(createProxyObject);

export type ExposedInterface = typeof createProxyObject;
```

```ts
// main
import { wrap } from 'comlink';
import { ExposedInterface } from './worker';
import MyWorker from './worker?worker';

const worker = new MyWorker();

const wrappedWorker = wrap(worker);

const remoteWorker = await wrappedWorker();

// `someOtherObject` should be `Promise>` 🚫
const otherObject = await remoteWorker.someOtherObject;

// `getSomeOtherObject` properly infers `Promise>` ✅
const objectViaGetter = await remoteWorker.getSomeOtherObject();

```
Example on Stackblitz:
https://stackblitz.com/edit/vitejs-vite-ml9mpl?file=src%2Fmain.ts&file=src%2Fworker.ts&terminal=dev