BUG: Theme preview not referencing the correct border stylings

### Checks

- [x] I have checked that this issue has not already been reported.

- [x] I am using the latest version of Flow Launcher.

- [x] I am using the prerelease version of Flow Launcher.

### Problem Description

Theme preview not referencing the correct border stylings. As you can see in the attached GIF. Switching between themes in a different order results in a different border styling which is not the original themes styling either.

### To Reproduce

1. Go through the selection of themes. The theme previews won't show the correct border styling of the chosen theme.

### Screenshots

### Flow Launcher Version

2.1.3.16650

### Windows Build Number

Windows 11 25H2 26200.9445

### Error Log

_No response_

Start by reproducing the issue in Flow Launcher 2.1.3.16650 on Windows 11, cycling through the available themes in different orders. Inspect the theme preview and border-styling path to determine why the preview diverges from the selected theme. Done means every theme preview shows its correct original border styling regardless of switching order.

Written by the indexing model from the issue text.