Feature flag: remove CDN_ENABLED

There are some leftovers here. CDN is enabled by default to all projects.

Related #9779

Author: humitos

readthedocs/projects/models.py

@@ -1908,7 +1908,6 @@ def add_features(sender, **kwargs):
     UPDATE_CONDA_STARTUP = "update_conda_startup"
     CONDA_APPEND_CORE_REQUIREMENTS = "conda_append_core_requirements"
     ALL_VERSIONS_IN_HTML_CONTEXT = "all_versions_in_html_context"
-    CDN_ENABLED = "cdn_enabled"
     DOCKER_GVISOR_RUNTIME = "gvisor_runtime"
     RECORD_404_PAGE_VIEWS = "record_404_page_views"
     ALLOW_FORCED_REDIRECTS = "allow_forced_redirects"
@@ -1975,13 +1974,6 @@ def add_features(sender, **kwargs):
                 "when building with Sphinx"
             ),
         ),
-        (
-            CDN_ENABLED,
-            _(
-                "Proxito: CDN support for a project's public versions when privacy levels "
-                "are enabled."
-            ),
-        ),
         (
             DOCKER_GVISOR_RUNTIME,
             _("Build: Use Docker gVisor runtime to create build container."),

readthedocs/proxito/tests/test_full.py

@@ -1524,14 +1524,6 @@ def test_404_download(self):
 )
 class TestCDNCache(BaseDocServing):
 
-    def setUp(self):
-        super().setUp()
-        get(
-            Feature,
-            feature_id=Feature.CDN_ENABLED,
-            projects=list(Project.objects.all()),
-        )
-
     def _test_cache_control_header_project(self, expected_value, host=None):
         """
         Test the CDN-Cache-Control header on requests for `self.project`.