Inconsistency in populating State.info

It seems that the class `State` defines `info` as a dictionary, and env wrappers are getting away treating it as such:

```
@struct.dataclass
class State:
"""Environment state for training and inference."""
qp: brax.QP
obs: jp.ndarray
reward: jp.ndarray
done: jp.ndarray
metrics: Dict[str, jp.ndarray] = struct.field(default_factory=dict)
info: Dict[str, Any] = struct.field(default_factory=dict)
```
e.g.
https://github.com/google/brax/blob/a09f3e75390c1ff017565ba2acfa77e838535fd3/brax/envs/wrappers.py#L67

```
def reset(self, rng: jp.ndarray) -> brax_env.State:
state = self.env.reset(rng)
state.info['steps'] = jp.zeros(())
state.info['truncation'] = jp.zeros(())
return state
```

However, default environments use `self.sys.info` to get an `Info` class object, but it's dumped in favour of creating a completely empty dictionary.
e.g.
https://github.com/google/brax/blob/a09f3e75390c1ff017565ba2acfa77e838535fd3/brax/envs/hopper.py#L81

```
def reset(self, rng: jp.ndarray) -> brax_env.State:
"""Resets the environment to an initial state."""
rng, rng1, rng2 = jp.random_split(rng, 3)
qpos = self.sys.default_angle() + jp.random_uniform(
rng1, (self.sys.num_joint_dof,), -.005, .005)
qvel = jp.random_uniform(rng2, (self.sys.num_joint_dof,), -.005, .005)
qp = self.sys.default_qp(joint_angle=qpos, joint_velocity=qvel)
info = self.sys.info(qp)
obs = self._get_obs(qp)
reward, done, zero = jp.zeros(3)
metrics = {
'reward_forward': zero,
'reward_ctrl': zero,
'reward_healthy': zero,
}
return brax_env.State(qp, obs, reward, done, metrics)
```

So if I'm reading this right, the `State.info` is not supposed to be coming from `self.sys.info`? In which case, `self.sys.info` will never be returned as part of `State`. Is this intentional?