use same name & order for checkbox::new and helper

The helper function for the checkbox widget switched the order
and name of the arguments passed when creating the checkbox
widget. This just standardizes the order whether the dev is using
the helper or the associated function.

Continuation of https://github.com/iced-rs/iced/pull/1616

native/src/widget/helpers.rs

@@ -129,7 +129,7 @@ where
     Renderer: crate::text::Renderer,
     Renderer::Theme: widget::checkbox::StyleSheet + widget::text::StyleSheet,
 {
-    widget::Checkbox::new(is_checked, label, f)
+    widget::Checkbox::new(label, is_checked, f)
 }
 
 /// Creates a new [`Radio`].