Some message providers have an associated capability. For example
the mod/quiz:emailconfirmsubmission capability. At the moment,
we only show the preferences for the capabilities that the user
has in the system context.
That does not work for the example capability above. Typically
the capability will be overridden in one quiz, to allow for
Students, and the user will have the Student role in the course
context. Therefore, this message type does not appear on the
preferences page.
This fix corrects the logic, so that all message types that are
to the current user are displayed.
