ci: revert #6833 to see if it breaks tests

Author: soyuka

src/State/Provider/ContentNegotiationProvider.php

@@ -62,9 +62,9 @@ public function provide(Operation $operation, array $uriVariables = [], array $c
     private function addRequestFormats(Request $request, array $formats): void
     {
         foreach ($formats as $format => $mimeTypes) {
-            $existingMimeTypes = $request->getMimeTypes($format);
-            $newMimeTypes = array_unique(array_merge((array) $mimeTypes, $existingMimeTypes));
-            $request->setFormat($format, $newMimeTypes);
+            // $existingMimeTypes = $request->getMimeTypes($format);
+            // $newMimeTypes = array_unique(array_merge((array) $mimeTypes, $existingMimeTypes));
+            $request->setFormat($format, (array) $mimeTypes);
         }
     }