Fix 'undefined' in link preview generation

server/model/status_page.js

@@ -38,7 +38,7 @@ class StatusPage extends BeanModel {
      */
     static async renderHTML(indexHTML, statusPage) {
         const $ = cheerio.load(indexHTML);
-        const description155 = statusPage.description?.substring(0, 155);
+        const description155 = statusPage.description?.substring(0, 155) ?? "";
 
         $("title").text(statusPage.title);
         $("meta[name=description]").attr("content", description155);