Fix type annotation for _identity_client in auth config

Updated the type annotation for _identity_client to use Optional["IdentityClient"] for better type clarity. Also removed unnecessary whitespace in ve_middlewares.py.

Author: loveyana

veadk/a2a/ve_middlewares.py

@@ -207,7 +207,7 @@ def _extract_token(self, request: Request) -> tuple[Optional[str], bool]:
         """
         has_prefix = False
         token = None
-        
+
         if self.auth_method == "header":
             # Extract from Authorization header
             auth_header = request.headers.get("Authorization") or request.headers.get(

veadk/configs/auth_configs.py

@@ -56,7 +56,7 @@ class VeIdentityConfig(BaseSettings):
     """
 
     # Global singleton IdentityClient instance
-    _identity_client: "IdentityClient|None" = None
+    _identity_client: Optional["IdentityClient"] = None
 
     def get_endpoint(self) -> str:
         """Get the endpoint URL for Identity service.