- Ensure that organisations cannot be blocked. It currently has no
effect, as all blocked operations cannot be executed from an
organisation standpoint.
- Refactored the API route to make use of the `UserAssignmentAPI`
middleware.
- Make more use of `t.Run` so that the test code is more clear about
which block of code belongs to which test case.
- Added more integration testing (to ensure the organisations cannot be
blocked and some authorization/permission checks).