1.0.7: Fix viewer bug
Enable back face culling in `dm_control.viewer`. The viewer has its own set of default renderer flags, and when the `mjRND_CULL_FACE` flag was introduced in MuJoCo (https://github.com/deepmind/mujoco/commit/396fdf00c36b571cae2d4faee18dcca694919b8f) the viewer's default was not updated. Fixes https://github.com/deepmind/dm_control/issues/346. PiperOrigin-RevId: 472753294 Change-Id: I33e6f48ff1ea887d07765ae851651f6c106cb08b