Expanding some field types in the add index form result in nothing getting expanded

Problem/Motivation

Expanding some field types in the add index form result in nothing getting expanded.

Steps to reproduce

Try expanding language for example.

In this screenshot you can see Language is expanded with the minus shown, yet there are no nested fields.

Proposed resolution

Update the check for whether to expand or not to depend on whether there are actual results possible.

Remaining tasks

MR