Fixed: LTI exclusion to the hack that came back

(The hack came back... thought it was a goner.) Fixed LTI code to adapt
to Canvas change in how they include their hacky "Test Student" in every
course section.  This LTI now properly excludes Canvas' undocumented and
mostly-hidden hack that silently includes a "Test Student,
type=StudentViewEnrollment" in every section to enable the standard
"StudentView" for course participants.