`MujocoServerSensorManagerThreaded` launches thread on instantiation

[hello-binit]

I'm using MujocoServer without calling run or launch_server because I'm using it purely for visualization. I would expect instantiating an instance of MujocoServer to simply load in mjdata/mjmodel without spawning any threads/processes. However, it looks like MujocoServerSensorManagerThreaded launches a thread in the __init__ method. I think this should be moved to a run method, and MujocoServer should call MujocoServerSensorManagerThreaded's run method when its own run method is called.

stretch_mujoco/stretch_mujoco/mujoco_server_sensor_manager.py

Lines 111 to 112 in 8759874

	self.sensors_thread = threading.Thread(target=self._sensor_loop, daemon=True)
	self.sensors_thread.start()

Similarly, MujocoServerCameraManagerThreaded should wait to start the thread in its run method.

stretch_mujoco/stretch_mujoco/mujoco_server_camera_manager.py

Lines 268 to 269 in 8759874

	self.cameras_thread = threading.Thread(target=self._camera_loop, daemon=True)
	self.cameras_thread.start()