fix: lint issue

Author: koutaro-masaki

lib/src/material/widgets/options_dialog.dart

@@ -28,9 +28,7 @@ class _OptionsDialogState extends State<OptionsDialog> {
             itemCount: widget.options.length,
             itemBuilder: (context, i) {
               return ListTile(
-                onTap: widget.options[i].onTap != null
-                    ? widget.options[i].onTap!
-                    : null,
+                onTap: widget.options[i].onTap,
                 leading: Icon(widget.options[i].iconData),
                 title: Text(widget.options[i].title),
                 subtitle: widget.options[i].subtitle != null