Don't do full update for a manual_update

We can also mark a course as needing a full update if that's necessary, but in most cases, I don't want to redo work, I just want to quickly get an update processed.

app/controllers/courses_controller.rb

@@ -177,7 +177,7 @@ def tag
   def manual_update
     require_super_admin_permissions
     @course = find_course_by_slug(params[:id])
-    UpdateCourseStats.new(@course, full: true)
+    UpdateCourseStats.new(@course)
     redirect_to "/courses/#{@course.slug}"
   end