fix: prevent telemetry from leaking sensitive info

Prevent sensitive information from being logged in telemetry output by
assigning SecretStr type to sensitive fields. API keys, password from
KV store are now covered. All providers have been converted.

Signed-off-by: Sébastien Han <seb@redhat.com>

llama_stack/providers/remote/inference/vertexai/vertexai.py

@@ -8,6 +8,7 @@ from typing import Any
 
 import google.auth.transport.requests
 from google.auth import default
+from pydantic import SecretStr
 
 from llama_stack.apis.inference import ChatCompletionRequest
 from llama_stack.providers.utils.inference.litellm_openai_mixin import (
@@ -43,7 +44,7 @@ class VertexAIInferenceAdapter(OpenAIMixin, LiteLLMOpenAIMixin):
         except Exception:
             # If we can't get credentials, return empty string to let LiteLLM handle it
             # This allows the LiteLLM mixin to work with ADC directly
-            return ""
+            return SecretStr("")
 
     def get_base_url(self) -> str:
         """