refac: remove old sf 4 stuff

Author: gimler

EventListener/AutoAddMissingTranslations.php

@@ -53,10 +53,3 @@ public function onTerminate(TerminateEvent $event): void
         }
     }
 }
-
-// PostResponseEvent have been renamed into ResponseEvent in sf 4.3
-// @see https://github.com/symfony/symfony/blob/master/UPGRADE-4.3.md#httpkernel
-// To be removed once sf ^4.3 become the minimum supported version.
-if (!class_exists(TerminateEvent::class) && class_exists(PostResponseEvent::class)) {
-    class_alias(PostResponseEvent::class, TerminateEvent::class);
-}

EventListener/EditInPlaceResponseListener.php

@@ -128,10 +128,3 @@ public function onKernelResponse(ResponseEvent $event): void
         $event->getResponse()->setContent($content);
     }
 }
-
-// FilterResponseEvent have been renamed into ResponseEvent in sf 4.3
-// @see https://github.com/symfony/symfony/blob/master/UPGRADE-4.3.md#httpkernel
-// To be removed once sf ^4.3 become the minimum supported version.
-if (!class_exists(ResponseEvent::class) && class_exists(FilterResponseEvent::class)) {
-    class_alias(FilterResponseEvent::class, ResponseEvent::class);
-}