Hyrax dois urls should use account cname (#515)

* make sure everyone can write to /app/samvera/branding

* assert the host name for polymorphic_url to avoide url mix-ups

* use something more useful to arrive at account cname

config/initializers/hyrax-doi.rb

@@ -191,7 +191,7 @@ def client
 
   # Override Hyrax::DOI::DataCiteRegister.work_url to ensure that the url registered uses the tenant host
   def work_url(work)
-    account_cname = work["account_cname_tesim"]&.first
+    account_cname = Account.find_by(tenant: Apartment::Tenant.current)&.cname
     Rails.application.routes.url_helpers.polymorphic_url(work, host: account_cname)
   end