feat: Ask for restarting submission if form was changed

[Koc]

This is a follow-up for #2312 based on a comment https://github.com/nextcloud/forms/pull/2312#issuecomment-2336789918

https://github.com/user-attachments/assets/f1684beb-93b7-4de4-a2a9-3999d5fc78c0

:gift: Bonus

Added reset button

[Koc]

:spiral_notepad: Changes:

• fixed code review comments
• added reset button
• added :movie_camera: video with demo

cc @Chartman123