Git commits in Moodle 3.5.18 by Huong Nguyen

commit 821ee3f6d33424e83029d624fc4eecfaa1061604
Author: Huong Nguyen <huongn@moodle.com>
Date:   Thu, 22 Apr 2021 12:01:09 +0800
Tag:    v3.5.18

MDL-70720 Quiz: Improve capability checks when fetching users' best grades