community[patch]: change the class of qianfan_ak and qianfan_sk parameters (#24293)

- **Description:** we changed the class of two parameters to fix a bug,
which causes validation failure when using QianfanEmbeddingEndpoint

libs/community/langchain_community/embeddings/baidu_qianfan_endpoint.py

@@ -4,7 +4,7 @@ import logging
 from typing import Any, Dict, List, Optional
 
 from langchain_core.embeddings import Embeddings
-from langchain_core.pydantic_v1 import BaseModel, Field
+from langchain_core.pydantic_v1 import BaseModel, Field, SecretStr
 from langchain_core.utils import convert_to_secret_str, get_from_dict_or_env, pre_init
 
 logger = logging.getLogger(__name__)
@@ -13,10 +13,10 @@ logger = logging.getLogger(__name__)
 class QianfanEmbeddingsEndpoint(BaseModel, Embeddings):
     """`Baidu Qianfan Embeddings` embedding models."""
 
-    qianfan_ak: Optional[str] = None
+    qianfan_ak: Optional[SecretStr] = None
     """Qianfan application apikey"""
 
-    qianfan_sk: Optional[str] = None
+    qianfan_sk: Optional[SecretStr] = None
     """Qianfan application secretkey"""
 
     chunk_size: int = 16