After updating to 8.6.6 my new tab page looks misaligned

### Describe the bug

Hello. Yesterday I upgraded to v8.6.6 and now the new tab page is misaligned as you can see in the attached screenshot. It was working fine before updating.

### Expected behavior

The sites on speed dial should be centered just as the search bar.

### Screenshots


### OS

Windows 10

### OS - Others

_No response_

### Firefox Version

v135.0

### 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

- [ ] Light
- [ ] Dark
- [ ] Alpenglow (System: Light)
- [ ] Alpenglow (System: Dark)
- [x] 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_

No source file or test is named in the report. Reproduce the misalignment on Windows 10 with Firefox 135 and the Original Lepton setup at v8.6.6, then trace the new-tab speed-dial styling; done means the sites are centered like the search bar.

Written by the indexing model from the issue text.