MDL-70911 core_badges: Add navigation menu in classic

Manage backpacks page wasn't displaying the navigation and administration
menus when using classic theme (it's unrelated to changes done here).
This patch fixes this unexpected behaviour (raised thanks to behat tests).

badges/backpacks.php

@@ -29,8 +29,6 @@ $PAGE->set_context($context);
 
 require_login(0, false);
 require_capability('moodle/badges:manageglobalsettings', $context);
-// There should be an admin setting to completely turn off badges.
-$output = $PAGE->get_renderer('core', 'badges');
 
 $id = optional_param('id', 0, PARAM_INT);
 $action = optional_param('action', '', PARAM_ALPHA);
@@ -47,6 +45,8 @@ $PAGE->set_url($url);
 $PAGE->set_title(get_string('managebackpacks', 'badges'));
 $PAGE->set_heading($SITE->fullname);
 
+$output = $PAGE->get_renderer('core', 'badges');
+
 $msg = '';
 $msgtype = 'error';
 if ($action == 'delete' && $confirm && confirm_sesskey()) {