60b5cac066
Switch MJX DataJAX to use the CSR-format `M` as its primary sparse inertia representation, matching MuJoCo C `mjData.M`. This allows both `mjData.qM` and `mjModel.mapM2M` to be deleted in the future. PiperOrigin-RevId: 932433465 Change-Id: I194ffbfdba0cdd9c718277ee0d5de7ac20f2b06f