Validation on state in the cart

Summary: Fixes T1503

Test Plan:
* On blendtec reset to develop and git pull
* cd Plugin/Cart
* arc patch this diff
* go to localhost website.  Do an order, make sure state is select a state click submit
* state should become red

Reviewers: #everyone, jslemboski

Reviewed By: #everyone, jslemboski

Subscribers: jslemboski, orabpornpra, mclawson

Maniphest Tasks: T1503

Differential Revision: https://dev.blendtec.com/D1067