Don't process recommendations in OAI server mode.

module/VuFind/src/VuFind/OAI/Server.php

@@ -562,6 +562,7 @@ class Server
         $params->setLimit($limit);
         $params->getOptions()->disableHighlighting();
         $params->getOptions()->spellcheckEnabled(false);
+        $params->recommendationsEnabled(false);
         $params->setSort('last_indexed asc', true);
 
         // Construct a range query based on last indexed time: