FolderPicker does not show WSL (Linux) folders, while FileOpenPicker does

## Describe the bug

`FolderPicker` (`Microsoft.Windows.Storage.Pickers.FolderPicker`) does not show WSL (Windows Subsystem for Linux) folders/locations, while `FileOpenPicker` does show them correctly under the same conditions.

## Steps to reproduce the bug

**Prerequisites:** WSL is enabled and at least one Linux distribution is installed. WSL folders (e.g., `\\wsl$\Ubuntu`) are visible in Windows Explorer.

1. Launch an app using `Microsoft.Windows.Storage.Pickers.FolderPicker` (e.g., the [StoragePickers sample](https://github.com/nickom-dev/WindowsAppSDK-Samples/tree/main/Samples/StoragePickers/cs-sample))
2. Click **"Pick Single Folder"** to open the FolderPicker dialog
3. **Observe:** WSL locations (e.g., `\\wsl$\Ubuntu`) are **not shown** in the navigation pane or anywhere in the dialog

**Contrast with FileOpenPicker:**

4. In the same app, use `FileOpenPicker` → click **"Pick Single File"**
5. **Observe:** WSL locations **are shown** and files inside WSL folders can be browsed and picked

**Additional interesting behavior (transient visibility):**

6. First, use `FileOpenPicker` to navigate into a WSL folder and pick any file (e.g., `\\wsl$\Ubuntu\home\user\somefile.txt`)
7. Immediately after, open `FolderPicker` again
8. **Observe:** This one time, WSL folders **are temporarily visible** in the FolderPicker
9. Close the FolderPicker (pick a folder or cancel), then open `FolderPicker` again
10. **Observe:** WSL folders have **disappeared again**, even though the picker's remembered path (from last use) still points to a WSL location

## Expected behavior

`FolderPicker` should show WSL locations consistently, the same way `FileOpenPicker` does, matching the behavior of Windows Explorer.

## Screenshots

_N/A_

## NuGet package version

Microsoft.WindowsAppSDK 1.8.250916003

## Windows version

Windows 11

## Additional context

- The `FileOpenPicker` consistently shows WSL folders — this is a `FolderPicker`-only issue.
- The transient visibility after using `FileOpenPicker` in a WSL path suggests the dialog may be caching or inheriting some navigation state, but failing to enumerate WSL locations on its own.
- WSL folders appear as network locations (`\\wsl$\...`) in Windows Explorer, so this may be related to how `FolderPicker` enumerates network/virtual shell locations differently from `FileOpenPicker`.