Empty "extension domain" in builder but domain is present in JSON view

**Describe the bug**
When we upload BCOs from the GlyGen Server or view old BCOs, the "extension domain" page in builder is empty but it's present in the JSON or Tree view.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to 'https://biocomputeobject.org/builder?https://biocomputeobject.org/GLY_001158/DRAFT'
2. Click on 'Extension Domain' in the left-hand menu and it's empty
3. Click on 'Raw JSON view' in the left-hand menu
4. Scroll down to 'Extension Domain' and it contains Dataset categories information.

**Expected behavior**
The information in the "Extension Domain" of the BCO JSON, to be on the "Extension Domain" edit page on builder.

**Screenshots**
Empty "extension domain" in portal:

Present in JSON or Tree view:

**Desktop (please complete the following information):**
- OS: Windows
- Browser: Microsoft Edge
- Version: 130

Open the builder URL from the reproduction steps and compare the Extension Domain edit page with the Raw JSON and Tree views for BCO GLY_001158/DRAFT. Trace how the existing Extension Domain data is loaded into the builder; done means the Dataset categories shown in JSON also appear on the edit page.

Written by the indexing model from the issue text.