🎨 Fix typing annotation for semi-internal FastAPI.add_api_route() (#10240)

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

fastapi/applications.py

@@ -1056,7 +1056,7 @@ class FastAPI(Starlette):
     def add_api_route(
         self,
         path: str,
-        endpoint: Callable[..., Coroutine[Any, Any, Response]],
+        endpoint: Callable[..., Any],
         *,
         response_model: Any = Default(None),
         status_code: Optional[int] = None,