Inconsistent ux for open/closed state of issues/related issues/mrs

Follow up of gitlab-ce#35462

Speaking of ui redesign: I generally miss a coherent ci in the ui. For example, after adding related issue (that's a big improvement, btw.) there are now two different styles to say done/finished/closed/open...:

by text:

by icons:

My favorite: Text with a colored badge/tag background, like the "open" badge in the mr