Figure out a way of handling LTI error situations

[murhum1]

Currently there are recurrent issues with MyCourses (Moodle) LTI exercises, where something goes wrong while importing gradebook items, resulting in grades not being saved from A+ to MyCourses. This floods admins with error emails, while not getting any response from the course staff, since students don't see any error messages --> course staff at MyCourses end is not informed --> course staff does not fix by re-importing exercises or such. We should figure out a way to get these error situations to the MyCourses course staff, e.g. by showing errors to students so they'd report to their teachers, leading to a fix without requiring admin intervention.