[YTA-862] Fix client-side validation on exit survey form.
[YTA-862] Fix client-side validation on exit survey form.

xnejp03/assets-frontend,hmrc/assets-frontend,alexanderjamesking/assets-frontend,tmikus/assets-frontend,alexanderjamesking/assets-frontend,hmrc/assets-frontend,tmikus/assets-frontend,xnejp03/assets-frontend,xnejp03/assets-frontend,alexanderjamesking/assets-frontend,hmrc/assets-frontend,tmikus/assets-frontend