Description of problem:
In Service UI, when you use Tag Control element in your Dialog with a single value it doesn’t allow you to add to Shopping cart. 

I tried multiple tag control elements, same result.
This works in OPS UI.
This works with a Multi value tag control.


Version-Release number of selected component (if applicable):
Latest nightly build plus some UI-Component fixes

How reproducible:
100%

Steps to Reproduce:
1.  Create a dialog
2.  Select Tag control
3.  Select a catalog
4.  Set to multi values
5.  Crate a Catalog item using this dialog.
6.  Order from Service Catalog

Actual results:
Add to Shopping Cart is greyed out

Expected results:
Add to Shopping Cart is enabled and you can order your service.

Additional info:
See related BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1570613