Workflow Sidebar Menu no longer shows file extensions.

### Prerequisites

- [x] I am running the latest version of ComfyUI
- [ ] I have custom nodes enabled

### What happened?

Opening the sidebar to load a workflow, the files within the tree no longer show file extension names obfuscating workflows from other files like included models or png files. Seems to have no other effect on functionality.

I started with --disable-all-custom-nodes.

### Steps to Reproduce

1. Click "Workflows" on left side menu bar.
2. Click down into any organizational hierarchy you might have.
3. Observe the lack of filename extensions.

### How is this affecting you?

Visual/UI issue only

### ComfyUI Frontend Version

1.41.21

### Browser

Firefox

### Console Errors

```javascript
No errors, no logs, just missing filename extensions in the load workflow side menu.
```

### Logs

```shell

```

### Additional Context

If this is by some strange reason a chosen UI decision, please rethink it.

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-10409-Workflow-Sidebar-Menu-no-longer-shows-file-extensions-32c6d73d3650815fb314d2e010dd1268) by [Unito](https://www.unito.io)

Start by reproducing the issue in the Workflows sidebar, following the listed steps with custom nodes disabled. Inspect the frontend entry point that builds the workflow file tree and restore visible filename extensions without changing other behavior. Done means workflow, model, and PNG files are distinguishable in nested folders, with no console errors.

Written by the indexing model from the issue text.