cs: missing variable declaration

Author: soyuka

src/State/Processor/RespondProcessor.php

@@ -122,6 +122,7 @@ public function process(mixed $data, Operation $operation, array $uriVariables =
         $requestParts = parse_url($request->getRequestUri());
         if ($this->iriConverter && !isset($headers['Content-Location'])) {
             try {
+                $iri = null;
                 if ($hasData) {
                     $iri = $this->iriConverter->getIriFromResource($originalData);
                 } elseif ($operation->getClass()) {