Pinned tab icon is not aligned when scroller tab active

### Describe the bug

Icons for pinned tabs is not aligned when I've so many tabs opened.

Occur on *Photon-style* with the *Normal* density on *Firefox 135.0*

### Expected behavior

Icon aligned in the center, not bottom.

### Screenshots


### OS

Linux

### OS - Others

Arch Linux

### Firefox Version

135

### Distribution

- [ ] [Original Lepton](https://github.com/black7375/Firefox-UI-Fix)
- [x] [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

I've user.js default generated from Photon style.

user.js setup

```javascript
// Your settings
```

### Additional context

_No response_

Reproduce the issue in the Lepton photon-style configuration with Normal density and many open tabs on Firefox, then inspect the pinned-tab icon styling while the scroller tab is active. Done means the pinned tab icon is vertically centered rather than aligned to the bottom.

Written by the indexing model from the issue text.