Make Checkbox example with a hint work again

Use the Checkbox as it is intended to be used, passing a hash for the
hint.

Author: koppen

demo/test/components/previews/checkbox_preview.rb

@@ -55,7 +55,7 @@ def disabled_checked_check_box
   # the checkbox component.
 
   def checkbox_with_helper_text
-    render(Flowbite::InputField::Checkbox.new(attribute: :confirmation, form: form, hint: "I agree with the terms and conditions."))
+    render(Flowbite::InputField::Checkbox.new(attribute: :confirmation, form: form, hint: {content: "I agree with the terms and conditions."}))
   end
 
   # @!endgroup