Hydra `policy_kwargs` issue - SB3 expecting `List` and not `ListConfig`

There is a problem with passing the policy_kwargs to the SB3 algorithms. It is straightforward to define it in hydra:

However, the get_actor_critic_arch() method of SB3 cannot convert it because it is of type ListConfig and not List. I already tried to convert the list, but assigning it to cfg.algorithm.policy_kwargs.net_arch converts it again to a ListConfig.

I guess this prevents us from running hyperopt for the hidden layers and anything that involves a list of parameters. If we do not like to change the original SB3 code and maintain an own version of that function, we need to find another solution. I am not sure if this is worth a pull request for the original SB3 code, as I can imagine that many people nowadays use hydra.