Fix folder page to check rsp.status === 201 instead of rsp.ok

Matches the fix in configurable.js to only treat 201 Created as success,
preventing false 'Build scheduled' notifications when builds are rejected.

Author: LakshyaBagani

core/src/main/resources/hudson/views/BuildButtonColumn/icon.js

@@ -14,7 +14,7 @@ Behaviour.specify(
         method: "post",
         headers: crumb.wrap({}),
       }).then((rsp) => {
-        if (rsp.ok) {
+        if (rsp.status === 201) {
           notificationBar.show(message, notificationBar.SUCCESS);
         } else {
           notificationBar.show(failure, notificationBar.ERROR);