When deleting instance of meta enrolment, report shows event "Grouping deleted" instead of "Enrolment method deleted".

Test scenario:

1. Create a course.
2. Go to enrolment methods and add a meta enrolment. Register.
3. Go back to list of enrolment methods and delete the meta enrolment.
4. Go in course reports.
5. Confirm
   1. That log line for deleting method shows "Grouping deleted" instead of "Enrolent method deleted.

This bog appears in lib/classes/event/enrol_instance_deleted.php, at line 76 : in the get_name function, string is "eventgroupingdeleted".