I don't believe there is a way to hide that without using CSS. If you want to hide this for all Next Steps component, you can do it with the following CSS added globally:

crt-next-steps .next-steps-no-data-add-step-container {
	display: none;
}

If it's only for a specific Next Steps component, you'll need the Id of the Next Steps component (click it in the form designer and scroll to the bottom of the properties window titled "Element code"). For example, if the Id is "NextSteps_7j21u6n", you'd add the CSS like this: 

crt-next-steps#NextSteps_7j21u6n .next-steps-no-data-add-step-container {
	display: none;
}

Ryan