LQR.ipynb: Don't refer to global model from Renderer.
LQR.ipynb: Don't refer to global model from Renderer.

PiperOrigin-RevId: 477444216
Change-Id: I1e71d823428b1c4f60751720fe5b85d5ae98c5c2

deepmind/mujoco,deepmind/mujoco,deepmind/mujoco,deepmind/mujoco,deepmind/mujoco