Summary:
When a value $B.A is a ReferenceList, returning it in an Any column can cause
an "unmarshallable object" error, if the RecordSet happens to be storing
row_ids in the form of a nested RecordList object. This happened consistently
when $B.A started off as another type and got converted to ReferenceList.
A specific manifestation was when a reference column $B uses "A" as a display
column, and this column gets converted from Text to ReferenceList.
Test Plan: Added a test that reproduces the problem.
Reviewers: alexmojaki
Reviewed By: alexmojaki
Differential Revision: https://phab.getgrist.com/D3089