Integrate Services into main.dart and Update Providers

This commit refactors the main.dart file to include service initialization and dependency injection:

- RestApiUtility Initialization: Initialize the RestApiUtility with a mock API endpoint.
- Service Initialization: Initialize ChatService and TaskService with the created RestApiUtility.
- Dependency Injection: Pass the initialized services to MyApp constructor.
- Provider Update: Replace the ChangeNotifierProvider creation in MultiProvider to use the new ChatViewModel and TaskViewModel initialized with the respective services.

This setup allows for better separation of concerns and easier testing, as the services are now decoupled from the view models.

lib/main.dart

@@ -3,13 +3,32 @@ import 'views/main_layout.dart';
 import 'package:provider/provider.dart';
 import 'package:auto_gpt_flutter_client/viewmodels/task_viewmodel.dart';
 import 'package:auto_gpt_flutter_client/viewmodels/chat_viewmodel.dart';
+import 'package:auto_gpt_flutter_client/services/chat_service.dart';
+import 'package:auto_gpt_flutter_client/services/task_service.dart';
+import 'package:auto_gpt_flutter_client/utils/rest_api_utility.dart';
 
+// TODO: Update documentation throughout project for consistency
 void main() {
-  runApp(const MyApp());
+  // Initialize the RestApiUtility
+  final restApiUtility = RestApiUtility(
+      "https://ef4bfad4-dddd-4bad-a6d2-eb4c77e46759.mock.pstmn.io");
+
+  // Initialize the services
+  final chatService = ChatService(restApiUtility);
+  final taskService = TaskService(restApiUtility);
+
+  runApp(MyApp(
+    chatService: chatService,
+    taskService: taskService,
+  ));
 }
 
 class MyApp extends StatelessWidget {
-  const MyApp({Key? key}) : super(key: key);
+  final ChatService chatService;
+  final TaskService taskService;
+
+  const MyApp({Key? key, required this.chatService, required this.taskService})
+      : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -20,8 +39,10 @@ class MyApp extends StatelessWidget {
       ),
       home: MultiProvider(
         providers: [
-          ChangeNotifierProvider(create: (context) => TaskViewModel()),
-          ChangeNotifierProvider(create: (context) => ChatViewModel()),
+          ChangeNotifierProvider(
+              create: (context) => ChatViewModel(chatService)),
+          ChangeNotifierProvider(
+              create: (context) => TaskViewModel(taskService)),
         ],
         child: const MainLayout(),
       ), // Set MainLayout as the home screen of the app