Error when column-defaults refers to nonexistent column

[zarsky-broad]

From the casebook of the USER Liaison:
A user had an issue where clicking a specific entity type in the data tab would cause the app to crash, leaving them with a blank screen.

We diagnosed that the cause of the issue was that workspace-column-defaults were set for that entity type, and referred to columns that didn't occur in the data model.

To reproduce:

1. Set workspace column defaults that include a nonexistent column for the specified entity type in the shown array
2. Try to load that entity type in the data tab