Revert "Return class instead of class name"

This reverts commit f328f56.

The commit was causing the build for downstream projects to fail.
In application.rb the start_listening_for_events call triggers
business process builder which calls start_on_application_created
which eventually gets to the ApplicationForm, which if it has a
has_one_attached call will trigger a call to AWS client new,
which triggers a missing AWS region error.

Author: lorenyu

app/models/flex/business_process_builder.rb

@@ -53,7 +53,7 @@ def start(step_name, on: nil, &handler)
       end
 
       def start_on_application_form_created(step_name)
-        event_name = "#{case_class.application_form_class.name}Created"
+        event_name = "#{case_class.application_form_class}Created"
         start(step_name, on: event_name) do |event|
           case_class.new(application_form_id: event[:payload][:application_form_id])
         end

app/models/flex/case.rb

@@ -38,7 +38,7 @@ def self.business_process
     # Returns the application form class for this case class.
     # Subclasses can override this method to customize the application form class naming.
     def self.application_form_class
-      name.sub("Case", "ApplicationForm").constantize
+      name.sub("Case", "ApplicationForm")
     end
     attribute :application_form_id, :uuid