Selecting a multireference field in the builder isn't working

[MarkoStrassl]

When selecting a multireference field within the wire panel of the UESIO Builder, the expected child field selection panel fails to display. Instead, the panel disappears entirely, hindering the ability to work with child fields of the referenced collection.

Steps to reproduce:

1. Open the UESIO builder.
2. Navigate to a wire, which has at least one multireference field.
3. Click on the multireference field in the wire panel and try to select a child field of this reference.
4. Observe that the "SELECT FIELDS" field selection panel, which should allow selection of specific child fields from the reference collection, does not appear.

Expected behavior:

Upon selecting a multireference field in the wire panel, a child field selection panel should display. This panel should allow the user to choose specific child fields from the referenced collection for further configuration or interaction.