Convert action_name to symbol for CanCanCan authorization

Fix CanCanCan authorization by converting action_name to symbol.
In the context of implementing permissions in the Solidus Demo, we identified
that `action_name` in string format doesn't align with
CanCanCan's `authorize!` method expectations.
It needs to be in symbol format to be processed correctly.
This change ensures our authorization logic functions as intended
also for the new solidus admin views.

admin/app/controllers/solidus_admin/controller_helpers/authorization.rb

@@ -17,7 +17,7 @@ def authorize_solidus_admin_user!
  subject = authorization_subject
 
  authorize! :admin, subject
- authorize! action_name, subject
+ authorize! action_name.to_sym, subject
  end
 
  def authorization_subject