about:newtab missing website icons

### Describe the bug

The icons are not there. Just white. They're still fully functional. This happens even after a full reinstallation of firefox.

### Expected behavior

_No response_

### Screenshots

### OS

Windows 10

### OS - Others

_No response_

### Firefox Version

153.0.4

### Distribution

- [x] [Original Lepton](https://github.com/black7375/Firefox-UI-Fix)
- [ ] [Lepton's photon style](https://github.com/black7375/Firefox-UI-Fix/tree/photon-style)
- [ ] [Lepton's proton style](https://github.com/black7375/Firefox-UI-Fix/tree/proton-style)

### Theme

- [x] Light
- [ ] Dark
- [ ] Alpenglow (System: Light)
- [ ] Alpenglow (System: Dark)
- [ ] System Default
- [ ] Others: (e.g. [Photon Colors](https://addons.mozilla.org/en-US/firefox/addon/photon-colors/), [Google Chrome Dark](https://addons.mozilla.org/en-US/firefox/addon/google-chrome-dark/), [Fairytale Of Nature](https://addons.mozilla.org/en-US/firefox/addon/fairytale-of-nature/))

### Theme - More Info

_No response_

### `user.js` setup

user.js setup

```javascript
// Your settings
```

### Additional context

_No response_

The report names the about:newtab entry point but no source file or test. Start by reproducing the missing website icons on Firefox 153.0.4 for Windows 10 with the Original Lepton distribution and Light theme, then trace the styles affecting that page. Done means the icons render and remain functional as shown by the report’s expected behavior.

Written by the indexing model from the issue text.