"exactmeshinertia" is now only saved if its value is different than default.
"exactmeshinertia" is now only saved if its value is different than default.

PiperOrigin-RevId: 469848032
Change-Id: I9abdeccbf764f5e4267753c0e2bfdd42b3bec723

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