sorting fkd

[tttriple]

Currently when using tiny arrows, sorting doesnt happen. plz fix. ty.

This only happens with some (large) degree programmes and when all year classes are combined. For example here sorting works but here it doesn't.

The probable cause is that students might have multiple study rights in the same programme, which causes them to appear in the table many times. This leads to rows having same keys which means React cannot correctly identify which row is which.

To fix this, we should make sure that each student only has one entry in the backend response. But which study right should we choose if there are many?