Fix definition of "intersection-multi-agent-v1" with MultiAgentWrapper

[LucasAlegre]

This PR changes the register of "intersection-multi-agent-v1" to apply the MultiAgentWrapper on the register method.

The previous version is giving an error when importing highway-env with gymnasium 1.0 since MultiAgentWrapper(MultiAgentIntersectionEnv) is applying a wrapper to a class instead of an object.

[LucasAlegre]

Can this be merged asp @eleurent @jjshoots ? We need this for MO-Gymnasium Farama-Foundation/MO-Gymnasium#95

[ffelten]

Shouldn't you try to bump Gymnasium to 1.0 in this PR?

[LucasAlegre]

Shouldn't you try to bump Gymnasium to 1.0 in this PR?

It is not necessary on MO-Gymnasium side.

[pseudo-rnd-thoughts]

I think this issue is resolved on Gymnasium main, could you test locally to confirm?

[LucasAlegre]

I think this issue is resolved on Gymnasium main, could you test locally to confirm?

I got the same error using the last Gymnasium state on Github:

  File "/home/lucas/HighwayEnv/highway_env/envs/__init__.py", line 6, in <module>
    from highway_env.envs.intersection_env import *
  File "/home/lucas/HighwayEnv/highway_env/envs/intersection_env.py", line 428, in <module>
    TupleMultiAgentIntersectionEnv = MultiAgentWrapper(MultiAgentIntersectionEnv)
  File "/home/lucas/Gymnasium/gymnasium/core.py", line 310, in __init__
    assert isinstance(env, Env)

[pseudo-rnd-thoughts]

Ok, dont worry then

[LucasAlegre]

@pseudo-rnd-thoughts I guess it makes sense to make a new release for highway-env? The last one is from more than one year ago.

[pseudo-rnd-thoughts]

Yes, that is probably a good idea

[eleurent]

Thanks for this fix! Made a new release: v1.9.1