Bump django from 5.2.4 to 5.2.6 in /src/backend (#1360)

⬆️(backend) bump django from 5.2.4 to 5.2.6
    
Bumps [django](https://github.com/django/django) from 5.2.4 to 5.2.6.
- [Commits](https://github.com/django/django/compare/5.2.4...5.2.6)

---
updated-dependencies:
- dependency-name: django
  dependency-version: 5.2.6
  dependency-type: direct:production
...
    
Signed-off-by: dependabot[bot] <support@github.com>

src/backend/pyproject.toml

@@ -39,7 +39,7 @@ dependencies = [
     "django-redis==6.0.0",
     "django-storages[s3]==1.14.6",
     "django-timezone-field>=5.1",
-    "django==5.2.4",
+    "django==5.2.6",
     "django-treebeard==4.7.1",
     "djangorestframework==3.16.0",
     "drf_spectacular==0.28.0",