Conpherence - make empty comment submission behave like other apps

Summary: now we get a "you can't submit no text" error. Also puts the participant status updating inside the editor.

Test Plan: made empty comments and got the right error dialogue. made legit comments and they went through. made a new conpherence - work. edited title + picture on old conpherence - worked. tried to submit non-updates to title and image - correct error.

Reviewers: epriestley, chad

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2419

Differential Revision: https://secure.phabricator.com/D4734

src/applications/conpherence/controller/ConpherenceViewController.php

@@ -128,6 +128,7 @@ final class ConpherenceViewController extends
 
     $form =
       id(new AphrontFormView())
+      ->setWorkflow(true)
       ->setAction($this->getApplicationURI('update/'.$conpherence->getID().'/'))
       ->setFlexible(true)
       ->setUser($user)