Clean up block class for Jobs feature

In the directory app/assets/javascripts/jobs you'll notice a lot of components in the sidebar rely on a top level block class. We can't simply move this over to gl-display-block. There is some upstream CSS that specifically looks for this block class to apply other styles for the UI.

We shouldn't rely on a display class to apply other styles. Let's use this issue to replace all these instances and use gitlab-utility classes instead 🙏