convert NumPy RNG key data to uncommitted default-device-backed `jax.Array` data
Generally, we want to maintain that key data backing a `PRNGKeyArray` is a `jax.Array`. This change converts NumPy arrays on construction.
Co-authored-by: Yash Katariya <yashkatariya@google.com>
PiperOrigin-RevId: 748077900