[Bug] Image attachment previews and page covers no longer display in Desktop Client

### Bug Description

In the AppFlowy Desktop client, image files stored in a File Attachment field are no longer displaying an image preview/thumbnail.

The attachment itself is still present and the filename is displayed, but the image preview is missing.

This also affects pages where the attached image is being used as the page cover. When the attachment preview fails to load, the page cover is also removed/not displayed.

The same database record works correctly in the AppFlowy Web client, where both the attachment image preview and page cover display normally.

### How to Reproduce

1. Open a database containing a File Attachment property.
2. Attach an image such as a .jpg file.
3. Use that image as the page cover.
4. Open the record in the AppFlowy Web client.
- Image thumbnail displays correctly.
- Page cover displays correctly.
5. Open the same record in AppFlowy Desktop 0.13.2.
- The attachment filename is displayed, but the image thumbnail/preview is missing.
- The page cover using that image is also missing.

### Expected Behavior

The Desktop client should behave the same as the Web client:

- Image attachments should display a thumbnail/preview.
- Images used as page covers should display as the page cover.
- Existing image attachments should render consistently between Web and Desktop clients.

### Operating System

Windows 11

### AppFlowy Version(s)

13.2

### Screenshots

**Appflowy Web Client**

**Appflowy Desktop Client**

### Additional Context

Deployment: Self-hosted AppFlowy Cloud

This affects more than the visual attachment preview because images referenced by other page features, specifically page covers, also stop displaying in the Desktop client.