Handle very small screen

See https://gitlab.com/nathanael2/aelf-flutter/-/merge_requests/47#note_2436509668

Reported by @Krophil

![Image](https://github.com/user-attachments/assets/e4034350-448c-41c6-8240-ffc95673b113)

![Image](https://github.com/user-attachments/assets/42538000-b2ad-4019-9475-a15c1a165510)

![Image](https://github.com/user-attachments/assets/d4e1df51-ee5d-44f1-97b3-267e4f568e94)