refactor(tests): update model instantiation to use const for improved performance

test/features/feed/presentation/bloc/consultants_cubit/consultants_cubit_test.dart

@@ -31,7 +31,7 @@ void main() {
 
     test('getConsultants - успешная загрузка консультантов', () async {
       final testConsultants = [
-        FeedConsultantModel(
+        const FeedConsultantModel(
           slug: 'consultant-1',
           name: 'Консультант 1',
           description: 'Описание консультанта 1',
@@ -40,7 +40,7 @@ void main() {
           badges: [],
           ratingPlace: 1,
         ),
-        FeedConsultantModel(
+        const FeedConsultantModel(
           slug: 'consultant-2',
           name: 'Консультант 2',
           description: 'Описание консультанта 2',

test/features/feed/repositories/feed_repository_test.dart

@@ -28,9 +28,9 @@ void main() {
     });
 
     test('getFeedBlogPosts - успешное получение постов', () async {
-      final expectedModel = FeedBlogPostSettingsModel(
-        feedBlogPostList: const [],
-        meta: const Meta(
+      const expectedModel = FeedBlogPostSettingsModel(
+        feedBlogPostList: [],
+        meta: Meta(
           currentPage: 1,
           from: null,
           lastPage: 1,
@@ -56,9 +56,9 @@ void main() {
     test('getFeedBlogPosts - с запросом и страницей', () async {
       const query = 'тест';
       const page = 2;
-      final expectedModel = FeedBlogPostSettingsModel(
-        feedBlogPostList: const [],
-        meta: const Meta(
+      const expectedModel = FeedBlogPostSettingsModel(
+        feedBlogPostList: [],
+        meta: Meta(
           currentPage: page,
           from: null,
           lastPage: 2,
@@ -117,7 +117,7 @@ void main() {
     });
 
     test('getRecipes - успешное получение рецептов', () async {
-      final expectedRecipes = const RecipesPagination(
+      const expectedRecipes = RecipesPagination(
         recipesList: [],
       );
 
@@ -131,10 +131,10 @@ void main() {
     });
 
     test('getDiets - успешное получение диет', () async {
-      final expectedDiets = DietsPagination(
-        data: const [],
-        links: const Links(first: '', last: '', prev: null, next: null),
-        meta: const Meta(
+      const expectedDiets = DietsPagination(
+        data: [],
+        links: Links(first: '', last: '', prev: null, next: null),
+        meta: Meta(
           currentPage: 1,
           from: null,
           lastPage: 1,
@@ -169,10 +169,10 @@ void main() {
     });
 
     test('getPlans - успешное получение планов', () async {
-      final expectedPlans = PlanPaginationModel(
-        data: const [],
-        links: const Links(first: '', last: '', prev: null, next: null),
-        meta: const Meta(
+      const expectedPlans = PlanPaginationModel(
+        data: [],
+        links: Links(first: '', last: '', prev: null, next: null),
+        meta: Meta(
           currentPage: 1,
           from: null,
           lastPage: 1,
@@ -210,10 +210,10 @@ void main() {
 
     test('getBlogPostComments - успешное получение комментариев', () async {
       const postId = '1';
-      final expectedComments = CommentModel(
+      const expectedComments = CommentModel(
         data: [],
-        links: const Links(first: '', last: '', prev: null, next: null),
-        meta: const Meta(
+        links: Links(first: '', last: '', prev: null, next: null),
+        meta: Meta(
           currentPage: 1,
           from: null,
           lastPage: 1,
@@ -278,10 +278,10 @@ void main() {
     });
 
     test('getConsultants - успешное получение консультантов', () async {
-      final expectedConsultants = FeedConsultantPaginationModel(
-        data: const [],
-        links: const Links(first: '', last: '', prev: null, next: null),
-        meta: const Meta(
+      const expectedConsultants = FeedConsultantPaginationModel(
+        data: [],
+        links: Links(first: '', last: '', prev: null, next: null),
+        meta: Meta(
           currentPage: 1,
           from: null,
           lastPage: 1,