feat: add static embedding metadata to dynamic model listings for providers using OpenAIMixin (#3547)

# What does this PR do?

- remove auto-download of ollama embedding models
- add embedding model metadata to dynamic listing w/ unit test
- add support and tests for allowed_models
- removed inference provider models.py files where dynamic listing is
enabled
- store embedding metadata in embedding_model_metadata field on
inference providers
- make model_entries optional on ModelRegistryHelper and
LiteLLMOpenAIMixin
- make OpenAIMixin a ModelRegistryHelper
- skip base64 embedding test for remote::ollama, always returns floats
- only use OpenAI client for ollama model listing
- remove unused build_model_entry function
- remove unused get_huggingface_repo function


## Test Plan

ci w/ new tests

llama_stack/providers/remote/inference/azure/azure.py

@@ -14,14 +14,12 @@ from llama_stack.providers.utils.inference.litellm_openai_mixin import (
 from llama_stack.providers.utils.inference.openai_mixin import OpenAIMixin
 
 from .config import AzureConfig
-from .models import MODEL_ENTRIES
 
 
 class AzureInferenceAdapter(OpenAIMixin, LiteLLMOpenAIMixin):
     def __init__(self, config: AzureConfig) -> None:
         LiteLLMOpenAIMixin.__init__(
             self,
-            MODEL_ENTRIES,
             litellm_provider_name="azure",
             api_key_from_config=config.api_key.get_secret_value(),
             provider_data_api_key_field="azure_api_key",

llama_stack/providers/remote/inference/azure/models.py

@@ -1,28 +0,0 @@
-# Copyright (c) Meta Platforms, Inc. and affiliates.
-# All rights reserved.
-#
-# This source code is licensed under the terms described in the LICENSE file in
-# the root directory of this source tree.
-
-from llama_stack.providers.utils.inference.model_registry import (
-    ProviderModelEntry,
-)
-
-# https://learn.microsoft.com/en-us/azure/ai-foundry/openai/concepts/models?tabs=global-standard%2Cstandard-chat-completions
-LLM_MODEL_IDS = [
-    "gpt-5",
-    "gpt-5-mini",
-    "gpt-5-nano",
-    "gpt-5-chat",
-    "o1",
-    "o1-mini",
-    "o3-mini",
-    "o4-mini",
-    "gpt-4.1",
-    "gpt-4.1-mini",
-    "gpt-4.1-nano",
-]
-
-SAFETY_MODELS_ENTRIES = list[ProviderModelEntry]()
-
-MODEL_ENTRIES = [ProviderModelEntry(provider_model_id=m) for m in LLM_MODEL_IDS] + SAFETY_MODELS_ENTRIES