Fix class enrollment notification to send email on approval of class …

…without grades

app/models/class_enrollment.rb

@@ -194,7 +194,8 @@ def disapproved_by_absence_for_situation
     end
 
     def notify_student_and_advisor
-      return if grade.nil?
+      new_record = id_changed? || id_previously_changed?
+      return if new_record
       return if !(
         saved_change_to_grade? ||
         saved_change_to_situation? ||