bug: add positive int validation for voting delay and min/max period

[wa0x6e]

Currently, the voting delay, and min/max end period form is accepting negative value, which will trigger "Out of bound error" on save.

We should add validation to this form to only accept positive number

[wa0x6e]

Passing an negative value in hours/minute crash the page with the error

Uncaught (in promise) Maximum recursive updates exceeded in component <Editable>. This means you have a reactive effect that is mutating its own dependencies and thus recursively triggering itself. Possible sources include component template, render function, updated hook or watcher source function.```

[wa0x6e]

Getting the same error with the proposal threshold input