Fix fatal in Maniphest

Summary:
Fixes T9596.

Was unable to navigate to a task in Maniphest.

Test Plan: navigate to that task.

Reviewers: #blessed_reviewers, epriestley, avivey, tycho.tatitscheff

Reviewed By: avivey, tycho.tatitscheff

Subscribers: tycho.tatitscheff, avivey, Korvin

Maniphest Tasks: T9596

Differential Revision: https://secure.phabricator.com/D14300

src/applications/maniphest/controller/ManiphestTaskDetailController.php

@@ -418,9 +418,9 @@ final class ManiphestTaskDetailController extends ManiphestController {
       id(new PhabricatorActionView())
         ->setName(pht('Create Subtask'))
         ->setHref($this->getApplicationURI("/task/create/?parent={$id}"))
-        ->setIcon('fa-level-down'))
+        ->setIcon('fa-level-down')
         ->setDisabled(!$can_create)
-        ->setWorkflow(!$can_create);
+        ->setWorkflow(!$can_create));
 
     $view->addAction(
       id(new PhabricatorActionView())