AC-3643 fixed logic affected by PHP8.1 compatibility issues

Author: sergiy-v

app/code/Magento/Elasticsearch/SearchAdapter/Query/Builder/Sort.php

@@ -92,7 +92,7 @@ public function getSort(RequestInterface $request)
             if (in_array($item['field'], $this->skippedFields)) {
                 continue;
             }
-            $attribute = $this->attributeAdapterProvider->getByAttributeCode($item['field']);
+            $attribute = $this->attributeAdapterProvider->getByAttributeCode((string)$item['field']);
             $fieldName = $this->fieldNameResolver->getFieldName($attribute);
             if (isset($this->map[$fieldName])) {
                 $fieldName = $this->map[$fieldName];

lib/internal/Magento/Framework/DataObject.php

@@ -120,6 +120,7 @@ public function unsetData($key = null)
      * @param string $key
      * @param string|int $index
      * @return mixed
+     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
      */
     public function getData($key = '', $index = null)
     {
@@ -128,7 +129,7 @@ public function getData($key = '', $index = null)
         }
 
         /* process a/b/c key as ['a']['b']['c'] */
-        if (strpos((string)$key, '/') !== false) {
+        if ($key !== null && strpos($key, '/') !== false) {
             $data = $this->getDataByPath($key);
         } else {
             $data = $this->_getData($key);