deposit form: When creating custom funding, the Funder field cannot be cleared

[aescling]

Package version (if known): v13.0.0

Describe the bug

When creating a new "custom funding" in the Awards/Grants section, after selecting a funder in the Funder field, pressing the X button to clear that field does nothing.

Steps to Reproduce

1. Under Awards/Grants, click "Add custom"
2. In the Funder field, select a funder
3. Click the X button at the right of the now-populated Funder field

Expected behavior

The field should be clearable.