docs: Documentation update for NVIDIA Inference Provider (#3840)

# What does this PR do?
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relevant issues if applicable. -->

<!-- If resolving an issue, uncomment and update the line below -->
<!-- Closes #[issue-number] -->
- Fix examples in the NVIDIA inference documentation to align with
current API requirements.

## Test Plan
<!-- Describe the tests you ran to verify your changes with result
summaries. *Provide clear instructions so the plan can be easily
re-executed.* -->
N/A

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

@@ -19,15 +19,6 @@ class NVIDIAInferenceAdapter(OpenAIMixin):
 
     """
     NVIDIA Inference Adapter for Llama Stack.
-
-    Note: The inheritance order is important here. OpenAIMixin must come before
-    ModelRegistryHelper to ensure that OpenAIMixin.check_model_availability()
-    is used instead of ModelRegistryHelper.check_model_availability(). It also
-    must come before Inference to ensure that OpenAIMixin methods are available
-    in the Inference interface.
-
-    - OpenAIMixin.check_model_availability() queries the NVIDIA API to check if a model exists
-    - ModelRegistryHelper.check_model_availability() just returns False and shows a warning
     """
 
     # source: https://docs.nvidia.com/nim/nemo-retriever/text-embedding/latest/support-matrix.html