Fix ComplexMessage error when values is undefined

src/p4/ComplexMessage.svelte

@@ -17,7 +17,7 @@
       if (isText) {
         el.appendChild(document.createTextNode(part));
       } else {
-        const value = values[part];
+        const value = values && values[part];
         if (value) {
           const node = document.createElement('a');
           node.href = value.href;