fix(serialization): Skip complex tensors when casting to real dtypes

[Eta0]

Avoid unsafe complex-to-real casts

This change resolves #206 by disallowing a real dtype passed to a TensorDeserializer from applying to complex-valued tensors, as complex-to-real casts would necessarily lose the imaginary component of such tensors.

Previously, only bool tensors were exempt from casts, so this expands on that exception.