Sambanova - LlamaGuard (#886)

# What does this PR do?

- Fix loading SambaNovaImpl issue
- Add LlamaGuard model support for inference

## Test Plan

Run the following unit test scripts and results

### Embedding
```
pytest -s -v --providers inference=sambanova llama_stack/providers/tests/inference/test_embeddings.py --inference-model meta-llama/Llama-3.2-11B-Vision-Instruct --env SAMBANOVA_API_KEY={SAMBANOVA_API_KEY}
```
```
llama_stack/providers/tests/inference/test_embeddings.py::TestEmbeddings::test_embeddings[-sambanova] SKIPPED (This test is only applicable for embedding models)
llama_stack/providers/tests/inference/test_embeddings.py::TestEmbeddings::test_batch_embeddings[-sambanova] SKIPPED (This test is only applicable for embedding models)

=================================================================================================================== 2 skipped, 1 warning in 0.32s ===================================================================================================================
```

### Vision
```
pytest -s -v --providers inference=sambanova llama_stack/providers/tests/inference/test_vision_inference.py --inference-model meta-llama/Llama-3.2-11B-Vision-Instruct --env SAMBANOVA_API_KEY={SAMBANOVA_API_KEY}
```

```
llama_stack/providers/tests/inference/test_vision_inference.py::TestVisionModelInference::test_vision_chat_completion_non_streaming[-sambanova-image0-expected_strings0] PASSED
llama_stack/providers/tests/inference/test_vision_inference.py::TestVisionModelInference::test_vision_chat_completion_non_streaming[-sambanova-image1-expected_strings1] PASSED
llama_stack/providers/tests/inference/test_vision_inference.py::TestVisionModelInference::test_vision_chat_completion_streaming[-sambanova] PASSED

=================================================================================================================== 3 passed, 1 warning in 2.68s ====================================================================================================================
```

### Text
```
pytest -s -v --providers inference=sambanova llama_stack/providers/tests/inference/test_text_inference.py::TestInference::test_chat_completion_streaming --env SAMBANOVA_API_KEY={SAMBANOVA_API_KEY}
```

```
llama_stack/providers/tests/inference/test_text_inference.py::TestInference::test_chat_completion_streaming[-sambanova] PASSED

=================================================================================================================== 1 passed, 1 warning in 0.46s ====================================================================================================================
```

```
pytest -s -v --providers inference=sambanova llama_stack/providers/tests/inference/test_text_inference.py::TestInference::test_chat_completion_non_streaming --env SAMBANOVA_API_KEY={SAMBANOVA_API_KEY}
```

```
llama_stack/providers/tests/inference/test_text_inference.py::TestInference::test_chat_completion_non_streaming[-sambanova] PASSED

=================================================================================================================== 1 passed, 1 warning in 0.48s ====================================================================================================================
```




## Before submitting

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

llama_stack/providers/remote/inference/sambanova/config.py

@@ -22,7 +22,7 @@ class SambaNovaImplConfig(BaseModel):
     )
 
     @classmethod
-    def sample_run_config(cls) -> Dict[str, Any]:
+    def sample_run_config(cls, **kwargs) -> Dict[str, Any]:
         return {
             "url": "https://api.sambanova.ai/v1",
             "api_key": "${env.SAMBANOVA_API_KEY}",