Allow `mujoco_playground._src.wrapper.Wrapper.render` to accept kwargs

Currently, the base wrapper class's render function is defined as
```python
def render(
self,
trajectory: List[mjx_env.State],
height: int = 240,
width: int = 320,
camera: Optional[str] = None,
scene_option: Optional[mujoco.MjvOption] = None,
modify_scene_fns: Optional[
Sequence[Callable[[mujoco.MjvScene], None]]
] = None,
) -> Sequence[np.ndarray]:
return self.env.render(
trajectory, height, width, camera, scene_option, modify_scene_fns
)
```
but when defining our own environments, users may have extra arguments for their render functions. Enabling kwargs would help solve potential silent bugs:
```python
def render(
self,
trajectory: List[mjx_env.State],
height: int = 240,
width: int = 320,
camera: Optional[str] = None,
scene_option: Optional[mujoco.MjvOption] = None,
modify_scene_fns: Optional[
Sequence[Callable[[mujoco.MjvScene], None]]
] = None,
**kwargs,
) -> Sequence[np.ndarray]:
return self.env.render(
trajectory, height=height, width=width, camera=camera, scene_option=scene_option, modify_scene_fns=modify_scene_fns, **kwargs
)
```