fix tag updates when copying Feature Services

The parsing method was trying to analyze the stringified JSON instead of
the parsed JSON.

src/js/main.js

@@ -1077,10 +1077,10 @@ require([
 
             // Update the new item's tags to make it easier to trace its origins.
             var newTags = description.tags;
-            newTags.push("source-" + description.id);
-            destinationPortal.updateDescription(destinationPortal.username, service.itemId, folder, JSON.stringify({
-                tags: newTags
-            }));
+            newTags.push("sourceId-" + description.id);
+            newTags.push("copied with ago-assistant");
+            destinationPortal.updateDescription(destinationPortal.username, service.itemId, folder, JSON.stringify({tags: newTags}));
+
             portal.serviceLayers(description.url)
                 .then(function(definition) {
                     var layerCount = definition.layers.length;

src/js/portal/content/updateDescription.js

@@ -11,14 +11,15 @@ export function updateDescription(username, id, folder, description) {
      * This is necessary because some of the item descriptions (e.g. tags and extent)
      * are returned as arrays, but the POST operation expects comma separated strings.
      */
-    for (let [key, value] of description) {
+    let payload = JSON.parse(description);
+    for (let key of Object.keys(payload)) {
+        let value = payload[key];
         if (value === null) {
-            description[key] = "";
+            payload[key] = "";
         } else if (value instanceof Array) {
-            description[key] = value.toString();
+            payload[key] = value.toString();
         }
     }
-    let payload = JSON.parse(description);
     payload.token = portal.token;
     payload.f = "json";
     let options = {