🚨(backend) follow Ruff 2024.2 style introduced in v0.3.0

We recently updated Ruff from 0.2.2 to v0.3, which introduced
Ruff 2024.2 style. This new style updated Ruff formatter's behavior,
making our make lint command fails.

Ruff 2024.2 style add a blank line after the module docstring.
Please take a look at Ruff ChangeLog to get more info.

src/backend/demo/management/commands/createsuperuser.py

@@ -2,6 +2,7 @@
 Management command overriding the "createsuperuser" command to allow creating users
 with their email and no username.
 """
+
 from django.contrib.auth import get_user_model
 from django.core.management.base import BaseCommand
 

src/backend/demo/tests/test_commands_create_demo.py

@@ -1,4 +1,5 @@
 """Test the `create_demo` management command"""
+
 from unittest import mock
 
 from django.core.management import call_command