🚨(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/core/api/__init__.py

@@ -1,4 +1,5 @@
 """People core API endpoints"""
+
 from django.conf import settings
 from django.core.exceptions import ValidationError
 

src/backend/core/api/permissions.py

@@ -1,4 +1,5 @@
 """Permission handlers for the People core app."""
+
 from django.core import exceptions
 
 from rest_framework import permissions

src/backend/core/api/serializers.py

@@ -1,4 +1,5 @@
 """Client serializers for the People core app."""
+
 from rest_framework import exceptions, serializers
 from timezone_field.rest_framework import TimeZoneSerializerField
 

src/backend/core/api/viewsets.py

@@ -1,4 +1,5 @@
 """API endpoints"""
+
 from django.contrib.postgres.search import TrigramSimilarity
 from django.db.models import Func, Max, OuterRef, Prefetch, Q, Subquery, Value