IBX-6017: Fixed validation of `ContentService::loadVersionInfoListByC…

…ontentInfo` input

For more details see #381

eZ/Publish/Core/Repository/ContentService.php

@@ -311,7 +311,7 @@ public function loadVersionInfoListByContentInfo(array $contentInfoList): array
                     sprintf(
                         'Element at position %d is not an instance of %s',
                         $idx,
-                        $contentInfo
+                        ContentInfo::class
                     )
                 );
             }