opened attribute to keep the component default open.
There are the following methods available to control the extra content for the collapsible.
toggle(): toggle the extra content
show(): show the extra content
hide(): hide the extra content
lion-collapsible fires an event on
invoker click to notify the component's current state. It is useful for analytics purposes or to perform some actions while expanding and collapsing the component.
@opened-changed: triggers when collapsible either gets opened or closed