I can't implement the check function if (element.classList.contains(__active)). That is, if the element already contains the class "active", then you need to remove this class from the element when you click on it.
Codepen
You can remove without checking. Try this:
const clickHandler = () => {
document.querySelector('.active')?.classList.remove('active');
};div {
color: red;
background: black;
margin-bottom: 16px
}
div.active {
color: black;
background: red;
}<div class="active">CHNAGE ME</div>
<button onClick="clickHandler()">CLICK TO CHANGE</button>