Collapses the element and sets its collapsed property to true.
The collapse() function returns a Promise that is resolved when the
element's collapsed property has been set to true.
To learn about the behavior of a collapsed element,
see the collapsed property.
You can also collapse an element when the page loads by using the Properties and Events panel in the Editor.
Note: The collapse() function doesn't remove elements from the DOM.
To soft delete an element from the DOM, use the delete() function.