MDL-69704 course: catch exception when calling get_course_content_items

When plugins are removed from disk, an exception is thrown when
calling component_callback_exists.
This exception should be catched here in order to load properly
the activity chooser (otherwise, the exception will be displayed
and no activity will appear).

course/classes/local/service/content_item_service.php

@@ -138,8 +138,12 @@ private function get_content_favourites(string $prefix, \context_user $userconte
             // Add any subplugins to the list of item types.
             $subplugins = $pluginmanager->get_subplugins_of_plugin('mod_' . $plugin->name);
             foreach ($subplugins as $subpluginname => $subplugininfo) {
-                if (component_callback_exists($subpluginname, 'get_course_content_items')) {
-                    $itemtypes[] = $prefix . $subpluginname;
+                try {
+                    if (component_callback_exists($subpluginname, 'get_course_content_items')) {
+                        $itemtypes[] = $prefix . $subpluginname;
+                    }
+                } catch (\moodle_exception $e) {
+                    debugging('Cannot get_course_content_items: ' . $e->getMessage(), DEBUG_DEVELOPER);
                 }
             }
         }