validate callback not executed when input is empty

[Saiberion]

If the value of the keyboard gets empty (e.g. backspace on last character) the validate callback is no longer executed.

[Mottie]

Hi @Saiberion!

No problem fixing this issue. There is also a bug from the last update where the class name for the accept button isn't correct, so it wasn't adding the valid/invalid class names either.