Limit training due date calculations to student role
Limit training due date calculations to student role

This will hopefully fix the performance problem for admins with hundreds of courses, when loading course pages and training pages.

KarmaHater/WikiEduDashboard,majakomel/WikiEduDashboard,KarmaHater/WikiEduDashboard,alpha721/WikiEduDashboard,majakomel/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,sejalkhatri/WikiEduDashboard,majakomel/WikiEduDashboard,alpha721/WikiEduDashboard,sejalkhatri/WikiEduDashboard,KarmaHater/WikiEduDashboard,alpha721/WikiEduDashboard,sejalkhatri/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,majakomel/WikiEduDashboard,alpha721/WikiEduDashboard,sejalkhatri/WikiEduDashboard,sejalkhatri/WikiEduDashboard,KarmaHater/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard,WikiEducationFoundation/WikiEduDashboard