Carousel control icons not aligned correctly

Created by: CarlosTorrecillas

The carousel control icons seem to be incorrectly aligned. If you take a look at the screenshots taken on the following issue: https://github.com/ng-bootstrap/ng-bootstrap/issues/1798 you should be able to see how the next icon should be aligned to the right as the prev icon is correcly aligned to the left.

When reporting a bug, include:

• Operating system and version: Windows 10
• Browser and version: Chrome 60.0.3112.113

In order to replicate that you can go to any of your carousels: https://getbootstrap.com/docs/4.0/components/carousel/ and add the background-color: black to .carousel-control-next-icon, .carousel-control-prev-icon and you'll see that straight away.