Import certificate without specifying the private key location

Current Situation

When importing a certificate in the "Manage Encryption Keys" view an error message is displayed if the value for the private key location is empty.

"BadRequestError: JSON DecodingFailure at .variables.encipherment_private_key_path: Got value 'null' with wrong type, expecting string"

Desired Behavior

It should be possible to import a certificate without specifying the location of the private key.