Allow creating outside/temp user via email in the assign to field in check-out assets page

When checking out an asset from view all assets you can add a user that is not in the system by entering the email and clicking enter

When using the check out assets page you lose this ability.

We want to use barcode for keys that are checked out by sub-teachers that don't have accounts in the system. We are not able to use the check out feature due to this limitation.