Unable to export MSDD model to pt or ONNX
Hi. MSDD is not an end-to-end model that performs speaker diarization from audio to label and it does not support ONNX export.
We are less than a month ahead of releasing end-to-end speaker diarizer, so please try using the new model once it gets released.  This issue is stale because it has been open for 30 days with no activity. Remove stale label or comment or this will be closed in 7 days. This issue was closed because it has been inactive for 7 days since being marked as stale.
**Describe the bug**

`EncDecDiarLabelModel` inherits `ExportableEncDecModel` which inherits `Exportable`. That means it should be exported to pt or ONNX file. When I ran the following code to export it, 
```
model = EncDecDiarLabelModel(cfg=modelConfig)
 msdd_model.export(output="msdd_model.pt", input_example=input_example)
```
I ran into errors:
```
AttributeError: 'EncDecDiarLabelModel' object has no attribute 'input_names'
```
The `input_names` attribute is defined in`Exportable`at [here](https://github.com/NVIDIA/NeMo/blob/1ba8bb1c623c2b7e938549002f5b77ab02fbe4bc/nemo/core/classes/exportable.py#L320). Is this an issue related to Python MRO (method resolution order)? 

**Steps/Code to reproduce bug**

I added some lines after [here](https://github.com/NVIDIA/NeMo/blob/1ba8bb1c623c2b7e938549002f5b77ab02fbe4bc/tests/collections/asr/test_diar_label_models.py#L155).
```
            input_example = (input_signal, input_signal_length, emb_vectors, targets)
            msdd_model.msdd._speaker_model.export(output="speaker_model.onnx")
            msdd_model.export(output="msdd_model.pt", input_example=input_example)
```

**Expected behavior**

Both`speaker_model.py`and`msdd_model.pt` are generated.

**Environment overview (please complete the following information)**

 - Environment location: Bare-metal
 - Method of NeMo install: check out the latest NeMo (commit 9a66eeeac2aa62541476bb4b66ae375b70d2db83) and run `pip install -e ".[asr]"` under the root folder.

**Environment details**

If NVIDIA docker image is used you don't need to specify these.
Otherwise, please provide:
- OS version: Ubuntu 24.04
- PyTorch version: 2.4.1+cu124
- Python version: 3.11.10

**Additional context**

Add any other context about the problem here.
GPU model: Nvidia L4 
