Cannot add a holdings to an existing instance - DRAFT

See videos showing it working in BugFest: https://drive.google.com/drive/folders/10lwqsEWcWS6fSSYpOEUbkhCtH7Q2tFx3?usp=sharing

Overview: Optional high-level description of problem A-M add description

Match on instance ID, then create a holdings (either after updating the instance or not) - should be able to work

Steps to Reproduce:

1. Log into FOLIO-snapshot as diku_admin
2. Click this
3. Select that
4. Etc

Expected Results: What should happen

Actual Results: What actually happened

Additional Information: See attached video or screenshot