style(demo_data): fix line break for product image save method

Simplify readability by unifying the method call into a single line. No functional changes.

engine/core/management/commands/demo_data.py

@@ -443,9 +443,7 @@ class Command(BaseCommand):
             alt=product.name,
             priority=priority,
         )
-        product_image.image.save(
-            image_path.name, ContentFile(image_content), save=True
-        )
+        product_image.image.save(image_path.name, ContentFile(image_content), save=True)
 
     @transaction.atomic
     def _create_demo_users(self, count: int) -> list: