fix(types): resolve mypy and pyright type checking errors

Author: AbdullahY36

scrapling/spiders/engine.py

@@ -48,7 +48,7 @@ def __init__(
             async def _fetch_robots(url: str, sid: str):
                 return await self.session_manager.fetch(Request(url, sid=sid))
 
-            self._robots_manager = RobotsTxtManager(_fetch_robots)
+            self._robots_manager: Optional[RobotsTxtManager] = RobotsTxtManager(_fetch_robots)
         else:
             self._robots_manager = None