Disable "Send Message" profile action if viewer is logged out

Summary: Fixes T9598.

Test Plan:
  - Used "Send Message" as a logged-in user.
  - Used "Send Message" as a logged-out user. The action was disabled and clicking it popped up a login dialog.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9598

Differential Revision: https://secure.phabricator.com/D14326

src/applications/people/controller/PhabricatorPeopleProfileController.php

@@ -72,11 +72,14 @@ final class PhabricatorPeopleProfileController
       $href = id(new PhutilURI('/conpherence/new/'))
         ->setQueryParam('participant', $user->getPHID());
 
+      $can_send = $viewer->isLoggedIn();
+
       $actions->addAction(
         id(new PhabricatorActionView())
           ->setIcon('fa-comments')
           ->setName(pht('Send Message'))
           ->setWorkflow(true)
+          ->setDisabled(!$can_send)
           ->setHref($href));
     }