[Bug]: Returned value of a generator function becomes enumerable

### 💻

- [ ] Would you like to work on a fix?

### How are you using Babel?

Other (Next.js, Gatsby, vue-cli, ...)

### Input code

```js
function * f(){}

var x = f();
for(p in x) console.log(p);
```

### Configuration file name

_No response_

### Configuration

_No response_

### Current and expected behavior

`input.js` prints nothing:
```console
$ node input.js # prints nothing
```
```console
$ node output.js
next
throw
return
toString
```

### Environment

[Reproduction on Babel's own REPL](https://babeljs.io/repl#?browsers=since%202015&build=&builtIns=false&corejs=3.21&spec=false&loose=false&code_lz=PTAEGcAsHsFcBsAmoAOAnAlgOwC6i9DpNgOYA0oARrHgPrYBu0A1gKagAUAhlsoZKzTgAlKky5WiAFAAzWFgDGODNCygAVKBkdhAbwC-UqQy5pQAD1ABeLToDcs6Gg4pQ2C6IWrw0eKwB08NAkLsJ2QA&debug=false&forceAllTransforms=false&shippedProposals=false&circleciRepo=&evaluate=false&fileSize=false&timeTravel=false&sourceType=script&lineWrap=true&presets=env%2Creact%2Cstage-2&prettier=true&targets=&version=7.20.2&externalPlugins=&assumptions=%7B%7D)

### Possible solution

_No response_

### Additional context

_No response_

Reproduce the example from input.js and compare Node's output with output.js generated through the Babel REPL using the shown presets. Trace the generator transformation entry point and its tests; done means the transformed generator's returned value does not expose enumerable properties during for-in iteration, matching native behavior.

Written by the indexing model from the issue text.