Ensure form errors always close when popup form submitted

Normally a form error will close itself when the user corrects the appropriate field, but for errors that affect multiple fields this may not happen.

(08:52:11 PM) dgg: Edit a Contribution (in popup) and set Net Amount and Fee Amount so they do NOT add up to Total
(08:52:19 PM) dgg: you'll get the validation error message.
(08:52:28 PM) dgg: now fix the amounts and Save again.
(08:52:35 PM) dgg: error message persists.