Merge branch '7.4' into 8.0

* 7.4:
  [SecurityBundle] Fix tests on Windows
  use the empty string instead of null as an array offset
  pass the empty string instead of null as key to array_key_exists()
  fix test setup
  [Validator] Review Turkish translations
  [Validator] Review Croatian translations
  [Console] Add #[Input] attribute to support DTOs in commands
  [Security][SecurityBundle] Dump role hierarchy as mermaid chart
  [DependencyInjection] Allow `Class::function(...)` and `global_function(...)` closures in PHP DSL for factories
  [VarExporter] Add support for exporting named closures
  [Validator] Review translations for Polish (pl)
  use the empty string instead of null as an array offset
  Review translations for Chinese (zh_TW)
  [Serializer] Adjust ObjectNormalizerTest for the accessor method changes from #61097
  fix merge
  [Security] Fix `HttpUtils::createRequest()` when the base request is forwarded
  map legacy options to the "sentinel" key when parsing DSNs
  fix setup to actually run Redis Sentinel/Cluster integration tests
  [Routing] Don't rebuild cache when controller action body changes

Author: nicolas-grekas

Slugger/AsciiSlugger.php

@@ -128,8 +128,8 @@ public function slug(string $string, string $separator = '-', ?string $locale =
 
         if (\is_array($this->symbolsMap)) {
             $map = null;
-            if (isset($this->symbolsMap[$locale])) {
-                $map = $this->symbolsMap[$locale];
+            if (isset($this->symbolsMap[$locale ?? ''])) {
+                $map = $this->symbolsMap[$locale ?? ''];
             } else {
                 $parent = self::getParentLocale($locale);
                 if ($parent && isset($this->symbolsMap[$parent])) {