style: remove unnecessary blank line

- Deleted an unnecessary blank line in the test file to improve code readability
- This change maintains the existing functionality without introducing any new logic or modifications

Author: fulleni

test/src/ht_data_inmemory_test.dart

@@ -63,7 +63,6 @@ void main() {
       });
 
       test('should throw BadRequestException if item with ID already exists',
-
           () async {
         await client.create(item1); // Create first time
         // Attempt to create again with the same ID