Fix "Undefined variable: form in eventhistory.phtml"

Please test a changed view at least once :(

fixes #7682

modules/monitoring/application/views/scripts/list/eventhistory.phtml

@@ -4,8 +4,6 @@
   <div style="margin: 1em" class="dontprint">
     <?= $this->translate('Sort by'); ?> <?= $this->sortControl->render($this); ?>
   </div>
-  <?= $form ?>
-  <br />
   <?= $this->widget('limiter', array('url' => $this->url, 'max' => $this->history->count())); ?>
   <?= $this->paginationControl($history, null, null, array('preserve' => $this->preserve)); ?>
 </div>