refactor(tests): replace 'final' with 'const' for improved performance in various test files

test/features/chat/presentation/widgets/chat_entry_widget_test.dart

@@ -16,7 +16,7 @@ void main() {
     Widget createTestWidget(ChatRoom chatRoom) {
       return MaterialApp.router(
         theme: ThemeHelper().themeData(),
-        localizationsDelegates: [
+        localizationsDelegates: const [
           S.delegate,
           GlobalMaterialLocalizations.delegate,
           GlobalWidgetsLocalizations.delegate,
@@ -47,7 +47,7 @@ void main() {
     }
 
     testWidgets('displays chat room with user name', (tester) async {
-      final chatRoom = ChatRoom(
+      const chatRoom = ChatRoom(
         id: 'test-id',
         users: Users(
           fromChatUser: ChatUser(
@@ -79,7 +79,7 @@ void main() {
     testWidgets('displays chat room with last message', (tester) async {
       final chatRoom = ChatRoom(
         id: 'test-id',
-        users: Users(
+        users: const Users(
           fromChatUser: ChatUser(
             id: 1,
             name: 'From User',
@@ -116,7 +116,7 @@ void main() {
     });
 
     testWidgets('displays chat room with unread messages count', (tester) async {
-      final chatRoom = ChatRoom(
+      const chatRoom = ChatRoom(
         id: 'test-id',
         users: Users(
           fromChatUser: ChatUser(
@@ -148,7 +148,7 @@ void main() {
     testWidgets('displays message from current user', (tester) async {
       final chatRoom = ChatRoom(
         id: 'test-id',
-        users: Users(
+        users: const Users(
           fromChatUser: ChatUser(
             id: 1,
             name: 'From User',
@@ -187,7 +187,7 @@ void main() {
     testWidgets('displays media attachment message', (tester) async {
       final chatRoom = ChatRoom(
         id: 'test-id',
-        users: Users(
+        users: const Users(
           fromChatUser: ChatUser(
             id: 1,
             name: 'From User',
@@ -228,7 +228,7 @@ void main() {
       final chatRoom = ChatRoom(
         id: 'test-id',
         users: Users(
-          fromChatUser: ChatUser(
+          fromChatUser: const ChatUser(
             id: 1,
             name: 'From User',
             profilePhotoPath: null,