Describe the bug
Error when trying to search for an item (number) in filter items search field:
instrument.js:109 TypeError: r?.primary?.toLowerCase is not a function

To Reproduce
Steps to reproduce the behavior:

1. Go to Add-on/Coverage Content Copy
2. Click on 'Create' to create a new item
3. Scroll down to 'Select Add-on/Coverage IDs'
4. Click Add Existing Select Add-on/Coverage IDs
5. In the Filter Items search box, type in a number
6. See error below

Expected behavior
Fix the error, users should be able to search for a number eg. IDs in the Filter Items search box without any issues

Screenshots

Note: the issue only happens when trying to search the id/number in the *filter items search field within the content, search is fine on the table list display:

Additional context
Slack thread here