Use CLI to update staking services

[jmoreira-valory]

The .run_service.sh script uses a custom script to execute update of staking services in this line:

https://github.com/valory-xyz/trader-quickstart/blob/ae7edbbd37a8379e147a199edecaf39c47adb26e/run_service.sh#L862

This was a temporary fix when the framework did not support to specify the token. Now that this has been fixed at framework level, so the run_service.sh script should use the CLI at this point, and remove the script update_service.py