Steps to reproduce:
1. Open Muse Sprite Generator
2. Enable the Custom Seed option
3. In Custom Seed field, enter forbidden characters - letters and symbols - such as "ASD-_!"
4. Press Enter
Expected result: User is unable to enter forbidden characters
Actual result: User is able to enter forbidden characters, but they don't get saved
Reproducible with: 2023.3.0a19 (Muse Sprite 1.0.0-pre.3)
Tested on: Windows 10