Set 'fast404_allow_anon_imagecache' back to 'FALSE' once the Fast 404 session cookie fix is released #3216

Summary

#3211 sets fast404_allow_anon_imagecache to TRUE in web/sites/default/includes/modules/settings.fast_404.php. With FALSE, drupal/fast_404 3.7.0 blocks missing image style derivatives for logged-in users too, because it matches SESS against cookie values instead of cookie names.

The upstream fix is tracked in fast_404 #3586450 (work item, merge request !18). It isn't merged yet, and 8.x-3.7 doesn't include it. Once a release ships the fix, set the value back to FALSE.

Details

• A drupal/fast_404 release includes the fix from #3586450.
• composer.json requires that drupal/fast_404 release or later.
• fast404_allow_anon_imagecache is FALSE in web/sites/default/includes/modules/settings.fast_404.php.
• The expectations in tests/phpunit/Drupal/EnvironmentSettingsTest.php and tests/phpunit/Drupal/SwitchableSettingsTest.php match the new value.
• subtestAhoyFast404() in .vortex/tests asserts that a missing derivative of an existing image gets the fast 404 for an anonymous user, and is still generated for a logged-in user.
• The Fast 404 settings list in .vortex/docs/content/development/modules/contributed-modules.mdx describes the new behavior.
• The installer fixtures are regenerated with ahoy update-snapshots.