bug #34786 [SecurityBundle] Use config variable in AnonymousFactory (martijnboers)

This PR was merged into the 4.4 branch.

Discussion
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[SecurityBundle] Use config variable in AnonymousFactory

| Q             | A
| ------------- | ---
| Branch?       | 4.4 and 5.0
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT

It looks like the `AnonymousFactory` was copied incorrectly in https://github.com/symfony/symfony/pull/33503 as it uses the old `$firewall` variable available in `SecurityExtension.php`. Changing this to `$config` yields the desired results

Commits
-------

8d850d2da4 When set, get secret from config variable

src/Symfony/Bundle/SecurityBundle/DependencyInjection/Security/Factory/AnonymousFactory.php

@@ -24,19 +24,19 @@ class AnonymousFactory implements SecurityFactoryInterface
     public function create(ContainerBuilder $container, $id, $config, $userProvider, $defaultEntryPoint)
     {
         if (null === $config['secret']) {
-            $firewall['anonymous']['secret'] = new Parameter('container.build_hash');
+            $config['secret'] = new Parameter('container.build_hash');
         }
 
         $listenerId = 'security.authentication.listener.anonymous.'.$id;
         $container
             ->setDefinition($listenerId, new ChildDefinition('security.authentication.listener.anonymous'))
-            ->replaceArgument(1, $firewall['anonymous']['secret'])
+            ->replaceArgument(1, $config['secret'])
         ;
 
         $providerId = 'security.authentication.provider.anonymous.'.$id;
         $container
             ->setDefinition($providerId, new ChildDefinition('security.authentication.provider.anonymous'))
-            ->replaceArgument(0, $firewall['anonymous']['secret'])
+            ->replaceArgument(0, $config['secret'])
         ;
 
         return [$providerId, $listenerId, $defaultEntryPoint];