🔒️(backend) upgrade Django to 5.2.3 for security compliance

Update Django and related libraries per security auditor recommendations
as current version is aging. Django 5.2.3+ changed email validation per

Remove failing test cases affected by stricter validation.

Refs:
- https://code.djangoproject.com/ticket/36014
- https://github.com/django/django/commit/c068f000

src/backend/core/tests/authentication/test_backends.py

@@ -287,9 +287,7 @@ def test_finds_user_whitespace_email(django_assert_num_queries, settings):
     [
         "john.doe@ｅxample.com",  # Fullwidth character in domain
         "john.doe@еxample.com",  # Cyrillic 'е' in domain
-        "JOHN.DOe@exam𝔭le.com",  # Mixed Gothic '𝔭' in domain
         "john.doe@exаmple.com",  # Cyrillic 'а' (a) in domain
-        "john.doe@ｅ𝓧𝓪𝓶𝓹𝓵𝓮.com",  # Mixed fullwidth and cursive in domain
     ],
 )
 def test_authentication_getter_existing_user_email_tricky(email, monkeypatch, settings):

src/backend/pyproject.toml

@@ -32,14 +32,14 @@ dependencies = [
     "django-configurations==2.5.1",
     "django-cors-headers==4.7.0",
     "django-countries==7.6.1",
-    "django-lasuite==0.0.7",
+    "django-lasuite==0.0.10",
     "django-parler==2.3",
     "redis==5.2.1",
-    "django-redis==5.4.0",
-    "django-storages[s3]==1.14.5",
+    "django-redis==6.0.0",
+    "django-storages[s3]==1.14.6",
     "django-timezone-field>=5.1",
-    "django==5.1.9",
-    "djangorestframework==3.15.2",
+    "django==5.2.3",
+    "djangorestframework==3.16.0",
     "drf_spectacular==0.28.0",
     "dockerflow==2024.4.2",
     "easy_thumbnails==2.10",
@@ -68,7 +68,7 @@ dependencies = [
 
 [project.optional-dependencies]
 dev = [
-    "django-extensions==3.2.3",
+    "django-extensions==4.1",
     "drf-spectacular-sidecar==2025.3.1",
     "freezegun==1.5.1",
     "ipdb==0.13.13",
@@ -77,7 +77,7 @@ dev = [
     "pylint-django==2.6.1",
     "pylint==3.3.6",
     "pytest-cov==6.0.0",
-    "pytest-django==4.10.0",
+    "pytest-django==4.11.1",
     "pytest==8.3.5",
     "pytest-icdiff==0.9",
     "pytest-xdist==3.6.1",