Correct return type on viewer.launch_passive.

PiperOrigin-RevId: 525753923
Change-Id: Idfff26e89deaeb37dd8b179106640f05c0deabb2

Author: nimrod-gileadi

python/mujoco/viewer.py

@@ -362,7 +362,7 @@ def launch_from_path(path: str) -> None:
   _launch_internal(run_physics_thread=True, loader=_file_loader(path))
 
 
-def launch_passive(model: mujoco.MjModel, data: mujoco.MjData) -> None:
+def launch_passive(model: mujoco.MjModel, data: mujoco.MjData) -> Handle:
   """Launches a passive Simulate GUI without blocking the running thread."""
   if not isinstance(model, mujoco.MjModel):
     raise ValueError(f'`model` is not a mujoco.MjModel: got {model!r}')