🚨(backend) fix linting issues after upgrading

The last upgrades introduced some linting issues.
This commit fixes them.

src/backend/core/api/__init__.py

@@ -1,4 +1,5 @@
 """Impress core API endpoints"""
+
 from django.conf import settings
 from django.core.exceptions import ValidationError
 
@@ -16,9 +17,9 @@ def exception_handler(exc, context):
     https://gist.github.com/twidi/9d55486c36b6a51bdcb05ce3a763e79f
     """
     if isinstance(exc, ValidationError):
-        if hasattr(exc, "message_dict"):
-            detail = exc.message_dict
-        elif hasattr(exc, "message"):
+        detail = exc.message_dict
+
+        if hasattr(exc, "message"):
             detail = exc.message
         elif hasattr(exc, "messages"):
             detail = exc.messages

src/backend/core/api/fields.py

@@ -1,4 +1,5 @@
 """A JSONField for DRF to handle serialization/deserialization."""
+
 import json
 
 from rest_framework import serializers

src/backend/core/api/permissions.py

@@ -1,4 +1,5 @@
 """Permission handlers for the impress 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 impress core app."""
+
 from django.db.models import Q
 from django.utils.translation import gettext_lazy as _
 

src/backend/core/api/viewsets.py

@@ -1,4 +1,5 @@
 """API endpoints"""
+
 from django.contrib.postgres.aggregates import ArrayAgg
 from django.db.models import (
     OuterRef,