issue: Activity Notice getLastRespondent()

This addresses issue 3647 where Internal Activity Alerts are never sent out
for both Tasks and Tickets. Upon initial investigation it appeared that we
set the `lastrespondent` property before we call
`onResponse()`/`onActivity()` so when we checked the Last Respondent it was
the same Agent posting the Reply so an email was never sent out. Upon moving
the `lastrespondent` property below the `onResponse()`/`onActivity()` calls,
it still grabbed the current Responding Agent. Looking deeper into
`getLastRespondent()` (for both Ticket and Task classes) I found that the
query we use to get the Last Response from an Agent on the Thread, grabs the
newly added Response. This is because the Thread Entry is added before we
call `getLastRespondent()` so we really need to grab the second record, not
the first. This updates the `limit()` clause from `1` to `1,1` to utilize
MySQL/MariaDB "LIMIT offest" so that we grab the second entry which is the
true Last Response. This also moves the `lastrespondent` property below the
`onResponse()`/`onActivity()` calls to ensure we don't return the current
Responding Agent.

include/class.task.php

@@ -361,7 +361,7 @@ function getLastRespondent() {
                     ))
                     ->values_flat('thread__entries__staff_id')
                     ->order_by('-thread__entries__id')
-                    ->limit(1)
+                    ->limit('1,1')
                 ))
                 ->first()
                 ?: false;
@@ -1039,16 +1039,17 @@ function postReply($vars, &$errors, $alert = true) {
         }
         */
 
-        $this->lastrespondent = $response->staff;
-        $this->save();
-
         // Send activity alert to agents
         $activity = $vars['activity'] ?: $response->getActivity();
         $this->onActivity( array(
                     'activity' => $activity,
                     'threadentry' => $response,
                     'assignee' => $assignee,
                     ));
+
+        $this->lastrespondent = $response->staff;
+        $this->save();
+
         // Send alert to collaborators
         if ($alert && $vars['emailcollab']) {
             $signature = '';

include/class.ticket.php

@@ -814,7 +814,7 @@ function getLastRespondent() {
                     ))
                     ->values_flat('staff_id')
                     ->order_by('-id')
-                    ->limit(1)
+                    ->limit('1,1')
                 ))
                 ->first()
                 ?: false;
@@ -3329,10 +3329,10 @@ function postReply($vars, &$errors, $alert=true, $claim=true) {
             $this->setStaffId($thisstaff->getId()); //direct assignment;
         }
 
-        $this->lastrespondent = $response->staff;
-
         $this->onResponse($response, array('assignee' => $assignee)); //do house cleaning..
 
+        $this->lastrespondent = $response->staff;
+
         $type = array('type' => 'message');
         Signal::send('object.created', $this, $type);