copy-current-url.js works only for the first social sharing block on a page

This patch reintroduces the issue of the popup message displaying for all instances when one instance is clicked. I see that the clicked element is no longer passed in (happened when converted from jQuery to vanilla javascript). So there are multiple issues that need fixing.

I had to do some additional work on the javascript so that the popup notification would only show for the button clicked.

Automatically closed - issue fixed for 2 weeks with no activity.