Fix exception when bookmark name is not defined

Author: jcbrand

src/headless/plugins/bookmarks/model.js

@@ -4,12 +4,12 @@ import converse from '../../shared/api/public.js';
 const { Strophe } = converse.env;
 
 class Bookmark extends Model {
-    get idAttribute () {
+    get idAttribute() {
         return 'jid';
     }
 
-    getDisplayName () {
-        return Strophe.xmlunescape(this.get('name')) || this.get('jid');
+    getDisplayName() {
+        return this.get('name') && Strophe.xmlunescape(this.get('name')) || this.get('jid');
     }
 }