fix: Windows checkboxChecked edge case (#21860)

Co-authored-by: Shelley Vohr <[email protected]>

shell/browser/ui/message_box_win.cc

@@ -184,8 +184,7 @@ DialogResult ShowTaskDialogUTF16(NativeWindow* parent,
   else
     button_id = cancel_id;
 
-  return std::make_pair(button_id,
-                        checkbox_checked ? verificationFlagChecked : false);
+  return std::make_pair(button_id, verificationFlagChecked);
 }
 
 DialogResult ShowTaskDialogUTF8(const MessageBoxSettings& settings) {