Old search bar without gray line around

### Describe the bug

Hello, please. When I activate the old search bar, the gray line around it is gone.
How can I get it back to look like the line next to the address bar?
(about:config, set browser.search.widget.new to false)

Firefox 154.0.1, Firefox-UI-Fix v8.7.6

### Expected behavior

_No response_

### Screenshots

### OS

Windows 11

### OS - Others

_No response_

### Firefox Version

Firefox 154.0.1

### Distribution

- [ ] [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](https://github.com/user-attachments/files/31884139/user.js)

user.js setup

```javascript
// Your settings
```

### Additional context

_No response_

Reproduce the issue in Firefox 154.0.1 on Windows 11 with the Light theme by setting about:config browser.search.widget.new to false. Inspect the styling for the old search bar and compare its border with the line next to the address bar; done means the gray outline is restored without changing the other toolbar styling.

Written by the indexing model from the issue text.