Creating a new Knowledge Environment modal view has wrong border

### Bug description

The corners are missing

<img width="1404" height="1102" alt="Image" src="https://github.com/user-attachments/assets/b323e351-8f97-4786-83d2-3e1782f24be5" />

### Operating system

macOs

### Installation Method

None

### Version

next (development version)

### Steps to reproduce

_No response_

### Relevant log output

```shell

```

### Additional context

_No response_