Fix use of created_entity

exp_legacy/module/modules/control/rockets.lua

@@ -195,8 +195,9 @@ Event.add(defines.events.on_rocket_launch_ordered, function(event)
 end)
 
 --- Adds a silo to the list when it is built
+--- @param event EventData.on_built_entity | EventData.on_robot_built_entity
 local function on_built(event)
-    local entity = event.created_entity
+    local entity = event.entity
     if entity.valid and entity.name == "rocket-silo" then
         local force = entity.force
         local force_name = force.name