Update Tensorflow Stub DType

[j3soon]

Environment information (required)

Not related.

Issue description

The tensorflow stub tensorboard/compat/tensorflow_stub/dtypes.py does not include certain types in the latest tensorflow tensorflow/python/framework/dtypes.py. Such as:

• types_pb2.DT_FLOAT8_E5M2_REF
• types_pb2.DT_FLOAT8_E4M3FN_REF
• types_pb2.DT_INT4_REF
• types_pb2.DT_UINT4_REF

These types exist in tensorboard/compat/proto/types.proto and in tensorflow/python/framework/dtypes.py.

I can open a PR to update the dtypes.py file according to the latest tensorflow code. However, I think it will require adding ml_dtypes as an extra dependency, and I'm not sure if this is the preferred approach.

[arcra]

Hmmm... I don't know if we want to include this dependency at this point. Honestly, I'm not well aware at this time of how this impacts users.

Those types seem to be noted as "experimental" in some way.

Have you experienced any issues with the tool because of this?

[j3soon]

Hi @arcra, I haven't encountered any issues with tensorboard, but I noticed that the stubs have significantly diverged from the main TensorFlow repository. Do you think we should update them now, or would it be better to resolve this when something breaks in the future?

[arcra]

Yes, honestly, we don't have bandwidth at the moment, and it's unclear if users are using these, and to what extent other parts of the code need to be updated. It looks like our tensor_util.py is the piece of code that would care about this, but we'd need to spend some time understanding if we want to and how to add support for these types there as well.

So I'd punt it until someone asks for support for this, but we can keep this open for now. Thanks for letting us know.