Ensure LMS passes correct group_id when querying content

TNL-23
I thought we decided on 404 for querying views and 400 for creation views? I'm fine with either one, but confused because you advised the following last Friday:

Greg Price
10:43 AM
If a student attempts to create a post in a cohort other than their own, that's a 400
Greg Price
10:44 AM
If a student attempts to access a post in a cohort other than their own, that's a 404