fix: ensure students can withdraw from tutorials
fix: ensure students can withdraw from tutorials

Specific permission is required, as tutorial changes can
be locked at the unit level.

jakerenzella/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,jakerenzella/doubtfire-api,jakerenzella/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,jakerenzella/doubtfire-api,jakerenzella/doubtfire-api,doubtfire-lms/doubtfire-api,jakerenzella/doubtfire-api,jakerenzella/doubtfire-api