fix(register): harden validation flow and extract register validation module

Author: TigerInYourDream

src/register/mod.rs

@@ -2,8 +2,9 @@ use makepad_widgets::*;
 
 pub mod register_screen;
 pub mod register_status_modal;
+mod validation;
 
 pub fn live_design(cx: &mut Cx) {
     register_screen::live_design(cx);
     register_status_modal::live_design(cx);
-}
+}