Fixed collapse initial unset issue

This one line of code is responsible for executing the initial configure of the collapsable element.

It happens that the collapsable element was not being set as such after the widget's construction. And if you called hide() or show() in the collapse widget it would execute this initial setting logic ( $(element).collapse() ) causing the element to necessarily toggle. In other situations, like integrated to a Modal, the collapse was crashing for good.