SAK-22818 fix unlabeled Grade Override form control


git-svn-id: https://source.sakaiproject.org/svn/gradebook/trunk@310247 66ffb92e-73f9-0310-93c1-f5514f145a0a
SAK-22817 a form control shouldn't be used as the table header


git-svn-id: https://source.sakaiproject.org/svn/gradebook/trunk@310248 66ffb92e-73f9-0310-93c1-f5514f145a0a