Improve batch registration error handling
Improve batch registration error handling

- Display non-validation errors with the usual popup
- Escape fields and error messages

picoCTF/picoCTF,royragsdale/picoCTF,picoCTF/picoCTF,royragsdale/picoCTF,royragsdale/picoCTF,picoCTF/picoCTF,royragsdale/picoCTF,royragsdale/picoCTF,picoCTF/picoCTF,royragsdale/picoCTF,royragsdale/picoCTF,picoCTF/picoCTF,picoCTF/picoCTF