Add `create_vulnerability_export` rule to user policy

ee/app/policies/ee/user_policy.rb

@@ -16,6 +16,9 @@ module EE
         updating_name_disabled_for_users &
         ~admin
       end.prevent :update_name
+
+      # TODO: Check this before removing WIP from MR
+      rule { user_is_self }.enable :create_vulnerability_export
     end
   end
 end