added comments and refactored code

lib/widgets/loading_notifier.dart

@@ -2,9 +2,14 @@ import 'package:flutter/material.dart';
 
 class LoadingNotifier extends StatelessWidget {
   const LoadingNotifier(
-      {super.key, required this.onDismissed, required this.message});
-  final void Function() onDismissed;
-  final String message;
+      {super.key,
+      required void Function() onDismissed,
+      required String message})
+      : _onDismissed = onDismissed,
+        _message = message;
+
+  final void Function() _onDismissed;
+  final String _message;
 
   @override
   Widget build(BuildContext context) {
@@ -26,11 +31,11 @@ class LoadingNotifier extends StatelessWidget {
                 child: CircularProgressIndicator(),
               ),
               Text(
-                message,
+                _message,
                 style: Theme.of(context).textTheme.titleSmall,
               ),
               IconButton(
-                onPressed: () => onDismissed(),
+                onPressed: () => _onDismissed(),
                 icon: Icon(Icons.close),
               )
             ],