chore: turn OpenAIMixin into a pydantic.BaseModel

- implement get_api_key instead of relying on LiteLLMOpenAIMixin.get_api_key
 - remove use of LiteLLMOpenAIMixin
 - add default initialize/shutdown methods to OpenAIMixin
 - remove __init__s to allow proper pydantic construction
 - remove dead code from vllm adapter and associated / duplicate unit tests
 - update vllm adapter to use openaimixin for model registration
 - remove ModelRegistryHelper from fireworks & together adapters
 - remove Inference from nvidia adapter
 - complete type hints on embedding_model_metadata
 - allow extra fields on OpenAIMixin, for model_store, __provider_id__, etc
 - new recordings for ollama

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

@@ -5,39 +5,22 @@
 # the root directory of this source tree.
 
 
-from llama_stack.providers.utils.inference.litellm_openai_mixin import LiteLLMOpenAIMixin
 from llama_stack.providers.utils.inference.openai_mixin import OpenAIMixin
 
 from .config import SambaNovaImplConfig
 
 
-class SambaNovaInferenceAdapter(OpenAIMixin, LiteLLMOpenAIMixin):
+class SambaNovaInferenceAdapter(OpenAIMixin):
+    config: SambaNovaImplConfig
+
+    provider_data_api_key_field: str = "sambanova_api_key"
+    download_images: bool = True  # SambaNova does not support image downloads server-size, perform them on the client
     """
     SambaNova Inference Adapter for Llama Stack.
-
-    Note: The inheritance order is important here. OpenAIMixin must come before
-    LiteLLMOpenAIMixin to ensure that OpenAIMixin.check_model_availability()
-    is used instead of LiteLLMOpenAIMixin.check_model_availability().
-
-    - OpenAIMixin.check_model_availability() queries the /v1/models to check if a model exists
-    - LiteLLMOpenAIMixin.check_model_availability() checks the static registry within LiteLLM
     """
 
-    def __init__(self, config: SambaNovaImplConfig):
-        self.config = config
-        self.environment_available_models: list[str] = []
-        LiteLLMOpenAIMixin.__init__(
-            self,
-            litellm_provider_name="sambanova",
-            api_key_from_config=self.config.api_key.get_secret_value() if self.config.api_key else None,
-            provider_data_api_key_field="sambanova_api_key",
-            openai_compat_api_base=self.config.url,
-            download_images=True,  # SambaNova requires base64 image encoding
-            json_schema_strict=False,  # SambaNova doesn't support strict=True yet
-        )
-
-    # Delegate the client data handling get_api_key method to LiteLLMOpenAIMixin
-    get_api_key = LiteLLMOpenAIMixin.get_api_key
+    def get_api_key(self) -> str:
+        return self.config.api_key.get_secret_value() if self.config.api_key else ""
 
     def get_base_url(self) -> str:
         """