🚩(project) add FRONTEND_SILENT_LOGIN_ENABLED feature flag

Not every project requires silent login.
This commit adds a new feature flag
FRONTEND_SILENT_LOGIN_ENABLED to enable or
disable silent login functionality.

src/backend/core/api/viewsets.py

@@ -2347,6 +2347,7 @@ class ConfigView(drf.views.APIView):
             "FRONTEND_CSS_URL",
             "FRONTEND_HOMEPAGE_FEATURE_ENABLED",
             "FRONTEND_JS_URL",
+            "FRONTEND_SILENT_LOGIN_ENABLED",
             "FRONTEND_THEME",
             "MEDIA_BASE_URL",
             "POSTHOG_KEY",

src/backend/core/tests/test_api_config.py

@@ -53,6 +53,7 @@ def test_api_config(is_authenticated):
         "FRONTEND_CSS_URL": "http://testcss/",
         "FRONTEND_HOMEPAGE_FEATURE_ENABLED": True,
         "FRONTEND_JS_URL": "http://testjs/",
+        "FRONTEND_SILENT_LOGIN_ENABLED": False,
         "FRONTEND_THEME": "test-theme",
         "LANGUAGES": [
             ["en-us", "English"],