[ticket/17176] Use Symfony name for event dispatcher

The previously used override of the names is no longer supported.

PHPBB3-17176

phpBB/config/default/container/services_twig.yml

@@ -11,7 +11,7 @@ services:
             - '%core.template.cache_path%'
             - '@ext.manager'
             - '@template.twig.loader'
-            - '@dispatcher'
+            - '@event_dispatcher'
             - []
         calls:
             - [setLexer, ['@template.twig.lexer']]