OEL-3602: Timeline vertical align. (#639)

* OEL-3602: Timeline vertical align.

* Apply suggestions from code review

Co-authored-by: Szilagyi Andras <aszilagyi@live.com>

---------

Co-authored-by: Szilagyi Andras <aszilagyi@live.com>

Author: julien-

src/themes/default/src/scss/_timeline.scss

@@ -19,9 +19,11 @@
       position: absolute;
       border-radius: 50%;
       border: 2px solid var(--bs-primary);
+      top: 6px;
       left: 0;
       width: 22px;
       height: 22px;
+      z-index: 1;
     }
 
     &::after {