[JAX] Avoid private implementation detail _ScalarMeta.
[JAX] Avoid private implementation detail _ScalarMeta.

The closest public approximation to type(jnp.float32) is `type[Any]`. Nothing is ever actually an instance of one of these types, either (they build `DeviceArray`s if instantiated.)

PiperOrigin-RevId: 469132170

deepmind/chex,deepmind/chex