Add prefix to object before spawning to avoid object registered twice in engine

[pengzhenghao]

What changes do you make in this PR?

• Please describe why you create this PR

now I add a prefix to Scenariotrafficlight manager's objects. From '162' to 'traffic_light_162'. This is because the Scenariotrafficmanager will also generate a traffc vehicle with name '162'. They will use the same name in the engine's registry. So when clear_objects from engine, the trafficmanager will remove '162'. Later when ScenarioTrafficLight manager want to remove '162', error will be raised in engine as the object already removed.

WE MIGHT ALSO WANT TO ADD PREFIX TO ALL OBJECTS SPAWN BY MANAGERS?

Checklist

• I have merged the latest main branch into current branch.
• I have run bash scripts/format.sh before merging.
• Please use "squash and merge" mode.

[pengzhenghao]

I actually come up with a better solution maybe when registering the object in the engine, we can ask the engine to append a prefix to the object name in so that the engine will remember which manager registered the objects

[pengzhenghao]

@QuanyiLi Is it possible that this PR will break save & restore scenarios utility? I am not sure.. If it LGTY then please merge.

[QuanyiLi]

It should be fine to do so. I wonder if we need to do this in engine.spawn_object where the object id can be obj.__class__.__name__ + uuid.