Fix the incomplete switch in `collectArrowInformationForSetOperation`

[barakmich]

Problem Statement

In pkg/schema/arrows.go in collectArrowInformationForSetOperation the switch over the core proto type is incomplete, missing *core.SetOperation_Child_FunctionedTupleToUserset.

#2374 highlights the issue with a comment but doesn't fix it (though it does provide a more helpful error message, and covers the case)

Solution Brainstorm

The implementation is very similar to Child_TupleToUserset in the same switch, if someone wants to go fix it really quick.