WorkflowException when validating content types with no workflow associated

[hvelarde]

Images and files have no workflow associated, this leads to the following exception on editing:

Traceback (innermost last):
  Module ZPublisher.Publish, line 138, in publish
  Module ZPublisher.mapply, line 77, in mapply
  Module ZPublisher.Publish, line 48, in call_object
  Module plone.z3cform.layout, line 66, in __call__
  Module plone.z3cform.layout, line 50, in update
  Module plone.dexterity.browser.edit, line 64, in update
  Module plone.z3cform.fieldsets.extensible, line 59, in update
  Module plone.z3cform.patch, line 30, in GroupForm_update
  Module z3c.form.group, line 145, in update
  Module plone.app.z3cform.csrf, line 21, in execute
  Module z3c.form.action, line 98, in execute
  Module z3c.form.button, line 315, in __call__
  Module z3c.form.button, line 170, in __call__
  Module plone.dexterity.browser.edit, line 33, in handleApply
  Module zope.event, line 31, in notify
  Module zope.component.event, line 24, in dispatch
  Module zope.component._api, line 136, in subscribers
  Module zope.component.registry, line 321, in subscribers
  Module zope.interface.adapter, line 585, in subscribers
  Module zope.component.event, line 32, in objectEventNotify
  Module zope.component._api, line 136, in subscribers
  Module zope.component.registry, line 321, in subscribers
  Module zope.interface.adapter, line 585, in subscribers
  Module sc.social.like.subscribers, line 148, in check_sharing_best_practices_on_editing
  Module plone.api.content, line 2, in get_state
  Module plone.api.validation, line 77, in wrapped
  Module plone.api.content, line 349, in get_state
  Module Products.CMFCore.WorkflowTool, line 263, in getInfoFor
WorkflowException: No workflow provides '${name}' information.

there's no workaround as the code that checks if the validator must be run is after the line that causes this error: https://github.com/collective/sc.social.like/blob/master/sc/social/like/subscribers.py#L120-L123