admin: UI glitch in debug-information

[tvdijen]

Specifics of your environment
N/A

Describe the bug
When testing an auhtsource from the admin-pages, an overview of attributes is shown. Underneath is also 'Debug information' with a json-array. Complex attributes like eduPersonTargetedID are shown there as an empty array

To Reproduce
Steps to reproduce the behavior:

1. Go to admin pages
2. Test an authsource that releases a complex attribute.
3. Scroll down to 'Debug information'
4. See the empty array as attribute-value

Expected behavior
The complex content should somehow be displayed

Screenshots or logs

Additional context
N/A