Conpherence - fix some ajax bugs

Summary: the people widget was returning a comma-delimited list of HTML nodes so kill that noise with some hsprintf action. We also weren't consistently updating the latest transaction id so simplify those codepaths (widgets vs pontificate) a bit. Fixes T3336.

Test Plan: left some messages, added some participants. noted that the people widget looked good and only the pertinent transactions were pulled down on updates.

Reviewers: epriestley, chad

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T3336

Differential Revision: https://secure.phabricator.com/D6180

src/applications/conpherence/controller/ConpherenceViewController.php

@@ -156,12 +156,9 @@ final class ConpherenceViewController extends
             'type' => 'hidden',
             'name' => 'latest_transaction_id',
             'value' => $latest_transaction_id,
-            'sigil' => 'latest-transaction-id',
-            'meta' => array(
-              'id' => $latest_transaction_id
-            )
+            'sigil' => 'latest-transaction-id'
           ),
-        ''))
+          ''))
       ->render();
 
     return $form;