[py] Fix driver service stop when starting browser fails (#15656)

[py] Fix Remote service stop

Author: cgoldberg

py/selenium/webdriver/remote/webdriver.py

@@ -354,7 +354,7 @@ def start_session(self, capabilities: dict) -> None:
             self.session_id = response.get("sessionId")
             self.caps = response.get("capabilities")
         except Exception:
-            if self.service is not None:
+            if hasattr(self, "service") and self.service is not None:
                 self.service.stop()
             raise