fix ruff linting issues and sort imports in thread-safety tests

Author: Deadpool2000

openapi_python_sdk/client.py

@@ -34,7 +34,7 @@ def client(self) -> Any:
         """
         if self._client is not None:
             return self._client
-        
+
         if not hasattr(self._thread_local, "client"):
             self._thread_local.client = httpx.Client(timeout=self.timeout)
         return self._thread_local.client

openapi_python_sdk/oauth_client.py

@@ -35,7 +35,7 @@ def client(self) -> Any:
         """
         if self._client is not None:
             return self._client
-        
+
         if not hasattr(self._thread_local, "client"):
             self._thread_local.client = httpx.Client(timeout=self.timeout)
         return self._thread_local.client