Repository: NVIDIA-Merlin/NVTabular

Issue:
[BUG] Getting error when loading the TF4Rec PyTorch model  to the TIS
**Describe the bug**
I am getting the following error when I load a trained TF4Rec PyTorch to TIS:

```
 | t4r_pytorch_pt  | 1       | UNAVAILABLE: Internal: ImportError: cannot import name '_convert_string2pytorch_dty |
|                 |         | pe' from 'nvtabular.inference.triton' (/nvtabular/nvtabular/inference/triton/__init |
|                 |         | __.py)                                                                              |
|                 |         |                                                                                     |
|                 |         | At:                                                                                 |
|                 |         |   /workspace/models/t4r_pytorch_pt/1/model.py(42): <module>                         |
|                 |         |   <frozen importlib._bootstrap>(219): _call_with_frames_removed                     |
|                 |         |   <frozen importlib._bootstrap_external>(848): exec_module                          |
|                 |         |   <frozen importlib._bootstrap>(686): _load_unlocked                                |
|                 |         |   <frozen importlib._bootstrap>(975): _find_and_load_unlocked                       |
|                 |         |   <frozen importlib._bootstrap>(991): _find_and_load                                |
+-----------------+---------+---------------------------------------------------------
```

**Steps/Code to reproduce bug**

Run the 02 and 03 notebooks Transformers4Rec tutorial [notebooks](https://github.com/NVIDIA-Merlin/Transformers4Rec/tree/main/examples/tutorial) to train the model. Then serve the model to TIS based on the instructions  given on the [inference notebook](https://github.com/NVIDIA-Merlin/Transformers4Rec/blob/main/examples/tutorial/04-Inference-with-Triton.ipynb).

`Oct-2019.parquet` Dataset can be downloaded from here: https://drive.google.com/drive/u/0/folders/1nTuG6UHWOEaZnBJj7YSIVvnphE1zGc1h

**Expected behavior**
Model should be loaded to the TIS without issue.

**Environment details (please complete the following information):**
 - Environment location: [Bare-metal, Docker, Cloud(specify cloud provider)] : Docker
 - Method of NVTabular install: [conda, Docker, or from source]: Docker `merlin-inference:21.11` and `merlin-pytoch-training:21.11` `
 Please do  `git pull origin main` && `pip install -e .` to pull the latest main branch.
   - If method of install is [Docker], provide `docker pull` & `docker run` commands used
 
This issue was also submitted by a user on TF4Rec GH repo- https://github.com/NVIDIA-Merlin/Transformers4Rec/issues/339



Discussion:

Resolving patch:
diff --git a/nvtabular/inference/triton/__init__.py b/nvtabular/inference/triton/__init__.py
--- a/nvtabular/inference/triton/__init__.py
+++ b/nvtabular/inference/triton/__init__.py
@@ -25,6 +25,7 @@
 
 from nvtabular.dispatch import _is_list_dtype, _is_string_dtype, _make_df  # noqa
 from nvtabular.inference.triton.ensemble import (  # noqa
+    _convert_string2pytorch_dtype,
     export_hugectr_ensemble,
     export_pytorch_ensemble,
     export_tensorflow_ensemble,


Test patch: