style(oauth): format the step-up scope check

pre-commit ruff-format wants this condition on one line.

Author: Bartok9

src/mcp/client/auth/oauth2.py

@@ -657,9 +657,7 @@ async def _auth_flow(self, request: httpx2.Request) -> AsyncGenerator[httpx2.Req
 
         response = yield request
 
-        step_up = (
-            response.status_code == 403 and extract_field_from_www_auth(response, "error") == "insufficient_scope"
-        )
+        step_up = response.status_code == 403 and extract_field_from_www_auth(response, "error") == "insufficient_scope"
 
         if response.status_code == 401 or step_up:
             async with self.context.lock: