js-executor: zero check and code cleanup
js-executor: zero check and code cleanup

volodymyr-babak/thingsboard,thingsboard/thingsboard,volodymyr-babak/thingsboard,volodymyr-babak/thingsboard,thingsboard/thingsboard,volodymyr-babak/thingsboard,volodymyr-babak/thingsboard,volodymyr-babak/thingsboard,thingsboard/thingsboard,thingsboard/thingsboard,thingsboard/thingsboard,thingsboard/thingsboard