feat(tests): updated tests coverage to 66.5%

test/features/plans/presentation/cubit/about_plan_state_test.dart

@@ -52,6 +52,25 @@ void main() {
       expect(state.planModel, plan);
       expect(state.chosenOptionIndex, 1);
     });
+
+    test('copyWith creates new instance with updated values', () {
+      const original = AboutPlanState(
+        isLoading: false,
+        error: null,
+        planModel: null,
+        chosenOptionIndex: 0,
+      );
+
+      final updated = original.copyWith(
+        isLoading: true,
+        chosenOptionIndex: 2,
+      );
+
+      expect(updated.isLoading, isTrue);
+      expect(updated.chosenOptionIndex, 2);
+      expect(updated.error, original.error);
+      expect(updated.planModel, original.planModel);
+    });
   });
 }