make slider trigger onChange also on click

[vsandvold]

This PR makes the slider call onChange also when the user clicks on the slider track, not just after dragging the slider thumbs.

Problem:
When clicking the slider track, onChange is not called, even though the input values are changed (and onInput is called). This prevents the eg. the search result page from updating the user's search when clicking on a slider filter.

Solution:
Since active is true while the user interacts with the slider, and false afterwards, we can use this state to trigger the onChange callback.