Captured and published videos from opencast have the wrong filetype

In case there is no filetype appended to the name of the opencast event
or the filetype is not in video, we just append '.mp4'. Otherwise moodle
will reject those files in the filepicker.

lib.php

@@ -315,6 +315,9 @@ public function get_listing($encodedpath = '', $page = '') {
         foreach ($videos as $video) {
             $listitem = array();
             $listitem['title'] = $video->title;
+            if (!file_extension_in_typegroup($video->title, $this->supported_filetypes())) {
+                $listitem['title'] = $video->title . '.mp4';
+            }
             $listitem['date'] = strtotime($video->start);
             $listitem['thumbnail'] = $video->thumbnail;
             $listitem['url'] = $video->url;