Remove duplicate set_auth_headers definition

Author: mcelicalderon

app/graphql/graphql_devise/mutations/base.rb

@@ -31,11 +31,6 @@ def controller
         context[:controller]
       end
 
-      def set_auth_headers(resource)
-        auth_headers = resource.create_new_auth_token
-        response.headers.merge!(auth_headers)
-      end
-
       def resource_class
         context[:resource_class]
       end