fix nvidia inference provider (#781)

# What does this PR do?

- fixes to nvidia inference provider to account for strategy update
- update nvidia templates

## Test Plan

```
llama stack run ./llama_stack/templates/nvidia/run.yaml --port 5000

LLAMA_STACK_BASE_URL="http://localhost:5000" pytest -v tests/client-sdk/inference/test_inference.py --html=report.html --self-contained-html
```
<img width="1288" alt="image"
src="https://github.com/user-attachments/assets/d20f9aea-525e-47de-a5be-586e022e0d55"
/>

**NOTE**
- vision inference broken
- tool calling broken
- /completion broken

cc @mattf @cdgamarose-nv  for improving NVIDIA inference adapter

## Sources

Please link relevant resources if necessary.


## Before submitting

- [ ] This PR fixes a typo or improves the docs (you can dismiss the
other checks if that's the case).
- [ ] Ran pre-commit to handle lint / formatting issues.
- [ ] Read the [contributor
guideline](https://github.com/meta-llama/llama-stack/blob/main/CONTRIBUTING.md),
      Pull Request section?
- [ ] Updated relevant documentation.
- [ ] Wrote necessary unit or integration tests.

llama_stack/providers/remote/inference/nvidia/openai_utils.py

@@ -279,7 +279,6 @@ def convert_chat_completion_request(
             nvext.update(top_k=strategy.top_k)
         elif isinstance(strategy, GreedySamplingStrategy):
             nvext.update(top_k=-1)
-            payload.update(temperature=strategy.temperature)
         else:
             raise ValueError(f"Unsupported sampling strategy: {strategy}")