Unable to override webpack-dev-server client.overlay configuration for renderer process

### Pre-flight checklist

- [X] I have read the [contribution documentation](https://github.com/electron/forge/blob/main/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [code of conduct](https://github.com/electron/electron/blob/main/CODE_OF_CONDUCT.md) that this project uses.
- [X] I have searched the issue tracker for a bug that matches the one I want to file, without success.

### Electron Forge version

6.2.1

### Electron version

25.2.0

### Operating system

macOS

### Last known working Electron Forge version

_No response_

### Expected behavior

Override webpack devServer.client.overlay config

### Actual behavior

Adding
```javascript
devServer: {
client: {
overlay: false
}
}
```
to webpack.renderer.config.ts has no effect at runtime - I continue to get overlay errors with this configuration set.

### Steps to reproduce

1. electron-forge project with webpack-typescript template + add react capability
2. trigger a runtime error in the renderer code
a. I have been getting this in project after configuring a two panel layout with react-split and react-monaco-editor in the right pane (without automaticLayout: true). Running the application and using the resizable divider leads to "ResizeObserver loop limit detected" runtime error. From what I can tell this is benign (which is wanted to suppress this error).
3. still observe the overlay for runtime error despite configuring it to not show. I've also observed this in the various forms of trying to disable the error (overlay: { runtimeErrors: false }, overlay: { runtimeErrors: (error) => {...} })

### Additional information

This seems potentially related to #2599