TrueNAS Scale: cannot select UPS driver

In TrueNAS-SCALE-21.02-ALPHA.1, the UPS driver cannot be set. Any selection from the list results in a "This field is required" validation message and the configuration cannot be saved.

Steps to reproduce:

1. Configure UPS service

2. Fill in all mandatory fields, including selecting ANY driver from the list.

3. Attempt to save

Results:

The driver field displays a validation message as if no value has been entered and the UPS service configuration cannot be saved.

Expected results:

The valid driver selection should be accepted.