BBB Activity Session Scheduling does not match 2.4 functionality

In v2.4 the session can not be accessed outside of a given start and end time by any user, including Admin. In 3.0 an admin user is still able to access the session even when students can't (Join session link is visible).

This needs to be fixed to match 2.4 for now, and in the future this functionality needs to be reviewed for how we want it to work.