fix: replace deprecated DCS session cookie settings

Use Django's native SESSION_COOKIE_SAMESITE and remove dead
DCS_SESSION_COOKIE_SAMESITE_FORCE_ALL settings (Fixes #38757).

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: Chessing234

lms/envs/common.py

@@ -989,9 +989,8 @@
 
 ############################### DJANGO BUILT-INS ###############################
 
-# django-session-cookie middleware
-DCS_SESSION_COOKIE_SAMESITE = 'None'
-DCS_SESSION_COOKIE_SAMESITE_FORCE_ALL = True
+# django-session-cookie middleware (deprecated DCS_* settings removed; see #38757)
+SESSION_COOKIE_SAMESITE = 'None'
 
 # LMS base
 LMS_BASE = 'localhost:18000'

lms/envs/devstack.py

@@ -474,9 +474,7 @@ def should_show_debug_toolbar(request):  # pylint: disable=missing-function-docs
 
 #####################################################################
 
-# django-session-cookie middleware
-DCS_SESSION_COOKIE_SAMESITE = 'Lax'
-DCS_SESSION_COOKIE_SAMESITE_FORCE_ALL = True
+SESSION_COOKIE_SAMESITE = 'Lax'
 
 ########################## THEMING  #######################
 # If you want to enable theming in devstack, uncomment this section and add any relevant

lms/envs/production.py

@@ -132,10 +132,6 @@ def get_env_setting(setting):
 
 DATA_DIR = path(DATA_DIR)  # noqa: F405
 
-# TODO: This was for backwards compatibility back when installed django-cookie-samesite (not since 2022).
-#       The DCS_ version of the setting can be DEPR'd at this point.
-SESSION_COOKIE_SAMESITE = DCS_SESSION_COOKIE_SAMESITE  # noqa: F405
-
 for feature, value in _YAML_TOKENS.get('FEATURES', {}).items():
     FEATURES[feature] = value