Improve service locator retrieval logic

The get method on the ContainerController left some to the imagination
when it comes to logging. This commit adds logging and makes transparant
which service was being loaded. This is usefull in case when the service
could not be loaded.

The other part is that the SF controller when the ResponseContext is
loaded. The unavailability of the StateHandlers response context id is
now checked.

src/Surfnet/StepupGateway/GatewayBundle/Container/ContainerController.php

@@ -54,6 +54,13 @@ public function setServiceContainer(ContainerInterface $container): void
 
     public function get(string $serviceName): mixed
     {
+        $logger = $this->container->get('logger');
+        $logger->notice(
+            sprintf(
+                'Reading the "%s" service from the container (temporary ContainerController solution)',
+                $serviceName
+            )
+        );
         try {
             $service = $this->container->get($serviceName);
         } catch (Exception) {

src/Surfnet/StepupGateway/GatewayBundle/Controller/SecondFactorController.php

@@ -46,6 +46,7 @@
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
 use Symfony\Component\Routing\Attribute\Route;
+use function is_null;
 use const FILTER_DEFAULT;
 use const FILTER_FORCE_ARRAY;
 
@@ -646,11 +647,20 @@ private function getStepupService()
      */
     private function getResponseContext($authenticationMode)
     {
-        return match ($authenticationMode) {
-            self::MODE_SFO => $this->get($this->get('gateway.proxy.sfo.state_handler')->getResponseContextServiceId()),
-            self::MODE_SSO => $this->get($this->get('gateway.proxy.sso.state_handler')->getResponseContextServiceId()),
+        // Select the state handler that matches the current authentication mode
+        $stateHandlerServiceId = match ($authenticationMode) {
+            self::MODE_SFO => 'gateway.proxy.sfo.state_handler',
+            self::MODE_SSO => 'gateway.proxy.sso.state_handler',
             default => throw new InvalidArgumentException('Invalid authentication mode requested'),
         };
+
+        // We then load the correct state handler service. And retrieve the ResponseContext service id that was set on it
+        $responseContextServiceId = $this->get($stateHandlerServiceId)->getResponseContextServiceId();
+        if (is_null($responseContextServiceId)) {
+            throw new RuntimeException('The RequestContext service id is not set on the state handler %s');
+        }
+        // Finally return the ResponseContext
+        return $this->get($responseContextServiceId);
     }
 
     /**