Unmounting a mount containing a file being edited by Code does not result in a "busy" warning

### What Happened?

Unmounting a mount containing a file being edited by Code does not result in a "busy" warning

### Steps to Reproduce

1. Mount e.g. a USB stick
2. Open a text file on that mount with Code
3. Ensure "Save files when changed" s OFF
4. Make some changes
5. Unmount the mount using Files (latest source)
6. No warning is given that the mount is in use by Code

### Expected Behavior

A user might expect to get a warning in this situation (although other text editors do not hold files open on the mount under similar circumstances either).

Fortunately Code handles the situation gracefully and gives the user the opportunity to save the file elsewhere or remount.

The desired behaviour is uncertain and suggestions are invited.

### OS Version

8.x (Circe)

### OS Architecture

amd64 (on most hardwares)

### Session Type

Secure Session (Wayland, This is the default)

### Software Version

Early Access or Compiled from git

### Log Output

```shell

```

### Hardware Info

_No response_

首先，使用 Files 和 Code，在已挂载的 USB 闪存盘上打开一个未保存的文件，复现该场景。明确是否需要警告，然后确定卸载警告的入口点，并围绕已达成一致的行为和回归测试定义完成标准。

由索引模型根据 Issue 内容生成。