feat(csst_dfs_client): change default timeout value to None in request functions

Change the default value of the `timeout` parameter from 300 to None
for all HTTP request methods (get, post, put, delete, post_bytesio,
and download_file) in the request module. This allows the requests
to use the system's default timeout behavior when no explicit timeout
is provided, improving flexibility and alignment with standard practices.

csst_dfs_client/common/request.py

@@ -34,7 +34,7 @@ def request_error_handler_decorator(func):
     return wrapper
 
 @request_error_handler_decorator
-def get(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
+def get(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", None)) -> requests.Response:
     return requests.get(
         url = get_request_url(endpoint),
         headers = auth_header(),
@@ -42,7 +42,7 @@ def get(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) ->
     )  
 
 @request_error_handler_decorator
-def post(endpoint: str, data: dict, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
+def post(endpoint: str, data: dict, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", None)) -> requests.Response:
     return requests.post(
         url = get_request_url(endpoint),
         headers = auth_header(),
@@ -51,7 +51,7 @@ def post(endpoint: str, data: dict, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOU
     )
 
 @request_error_handler_decorator
-def put(endpoint: str, data: Optional[dict] = None, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
+def put(endpoint: str, data: Optional[dict] = None, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", None)) -> requests.Response:
     return requests.put(
         url = get_request_url(endpoint),
         headers = auth_header(),
@@ -60,7 +60,7 @@ def put(endpoint: str, data: Optional[dict] = None, timeout = os.getenv("CSST_DF
     )
 
 @request_error_handler_decorator
-def delete(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
+def delete(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", None)) -> requests.Response:
     return requests.delete(
         url = get_request_url(endpoint),
         headers = auth_header(),
@@ -72,7 +72,7 @@ def post_file(endpoint: str, file_path: str, data: dict):
         return post_bytesio(endpoint, bytesio, data)
 
 @request_error_handler_decorator
-def post_bytesio(endpoint: str, file_bytes: IO, data: dict, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
+def post_bytesio(endpoint: str, file_bytes: IO, data: dict, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", None)) -> requests.Response:
     return requests.post(
         url = get_request_url(endpoint),
         headers = auth_header(),
@@ -82,7 +82,7 @@ def post_bytesio(endpoint: str, file_bytes: IO, data: dict, timeout = os.getenv(
         data = data, timeout = timeout
     )
 
-def download_file(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
+def download_file(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", None)) -> requests.Response:
     """
     下载指定endpoint对应的文件。