WebView returns blank page.

Upon running flet-webview with `flet run` instead of running the Python file itself using Python3, it returns a blank page. It works just fine when running it via Python3 but returns a blank page upon running with `flet run`.

<img width="1198" alt="Image" src="https://github.com/user-attachments/assets/d1c14061-f961-478f-9fb3-9ef90088a2d1" />