Fix for decode errors in bulk_email.tests.test_course_optout.py

common/djangoapps/track/views/__init__.py

lms/djangoapps/bulk_email/tests/test_course_optout.py

lms/djangoapps/instructor/views/instructor_dashboard.py

lms/djangoapps/instructor_task/api.py

lms/djangoapps/instructor_task/api_helper.py

lms/templates/experiments/user_metadata.html